Pain on one side, just under the ribs and wrapping toward the back, is the kind of pain people don't ignore. Patients who walk into our Beechnut office often put it simply: "I think it's my kidney." They may be right, but that ache can come from very different places. The two causes we worry about most are a stone moving through the urinary tract and an infection that has climbed up into the kidney. Sometimes both happen at once, and that combination is the most serious of all.
The medical team at the clinic put this guide together to help you read the clues that usually separate one from the other and, above all, to recognize when waiting is the wrong choice. It doesn't replace an exam.
Is it really your kidney?
Plenty of side pain has nothing to do with the kidneys. A strained muscle from lifting at work, hours bent over a job site or a fall gives pain that shifts when you twist, bend or press on the spot, and eases when you rest. That kind of pain rarely brings fever or changes in your urine.
Kidney pain behaves differently. It feels deeper, doesn't care much about how you're sitting and tends to bring company: urine that looks different, burning, nausea or a temperature. Those companions are what point the way.
What a kidney stone usually feels like
A small stone can sit quietly in the kidney for months. Trouble starts when it slides into the narrow tube leading to the bladder and blocks it for a while. The classic picture:
- Pain that hits suddenly and hard, on one side of the back or flank.
- It comes in waves, squeezing, letting up a little, then squeezing again.
- It travels toward the lower belly or groin as the stone moves down.
- You can't get comfortable, so you pace, sit, stand and pace again.
- Nausea and vomiting can show up just from how intense the pain is.
- Urine turns pink, red or brown from a small amount of blood.
A stone on its own usually doesn't cause fever early on. Once it nears the bladder, it can make you feel the urge to go often, which is easy to mistake for an infection.
What a kidney infection usually feels like
Most kidney infections start lower down, in the bladder, and work their way up. That's why many people remember a few days of discomfort when peeing that they brushed off. Once the kidney is involved, things feel different:
- A steady, dull ache in the side or lower back, more like heaviness than a cramp.
- Fever, sometimes with shaking chills.
- Feeling sick all over: worn out, achy, not hungry.
- Nausea or vomiting.
- Burning, cloudy or foul-smelling urine, though these aren't always there.
Put simply, a stone tends to announce itself with intensity and waves; an infection, with fever and feeling unwell.
Quick comparison
| Clue | More typical of a stone | More typical of a kidney infection |
|---|---|---|
| Onset | Sudden, out of nowhere | Builds over a day or more |
| Kind of pain | Waves, severe, can't sit still | Constant, dull, tender to the touch |
| Where it spreads | Lower belly and groin | Usually stays in the side |
| Fever | Uncommon at first | Common, sometimes with chills |
| Urine | Pink, red or brown | Cloudy, strong-smelling, burning |
Treat this as a rough guide, not a diagnosis. Some stones barely hurt, and some infections cause little or no fever, especially in older adults or people with weakened immune systems.
When both show up together
A stone that blocks urine flow can trap an infection behind it. If you have the wave-like pain of a stone plus fever or chills, don't wait for the stone to pass on its own. That situation usually needs hospital care to relieve the blockage, and water and rest at home won't fix it.
Side pain that can't wait: ER or 911
Any of these means the hospital emergency room is the right place (and 911 if nobody can drive you):
- Fever with side pain and chills, whether or not peeing hurts.
- Vomiting that won't let you keep water or fluids down, even small sips.
- Being unable to pee at all, or only a few drops despite the urge.
- Pain you can't bear, that nothing touches and that keeps you from talking calmly.
- Pregnancy with side pain, fever or blood in the urine; at this stage you don't wait it out.
- Fainting, confusion, cold clammy skin or severe weakness.
- Only one kidney or a kidney transplant, along with any of these symptoms.
Don't drive yourself with pain like this. Ask someone to take you.
What gets checked at the clinic
If the pain is manageable, there's no high fever and you can keep fluids down, a clinic visit helps sort things out. The medical team asks how the pain started, whether it comes and goes, whether you've had stones before and what color your urine has been. Then they examine your belly and tap gently on your back over each kidney to see which side reacts.
The urine sample is the key step. A urinalysis looks for two things at once: traces of blood, which lean toward a stone, and bacteria or white blood cells, which point to infection. When the sample shows white cells and bacteria but no blood, the pain is a dull ache rather than waves and none of the red flags listed above are present, we run the urine test at the clinic and, if there is an infection, your prescription is sent to your pharmacy the same day, plus a note on how much water to drink and which shifts in your side pain should bring you straight back to Beechnut. When it helps to identify the exact bacteria, a urine culture is also sent out, and that result takes a few days.
Depending on your case, the team may also suggest:
- A blood test to see how well your kidneys are filtering and whether there are signs of infection in the body.
- An abdominal ultrasound, which the clinic performs, to look at the kidneys without radiation, for example to check whether one is swollen from a blockage. Some scans call for an empty stomach, so phone ahead and we'll walk you through the prep.
- If you need a CT scan or other imaging we don't offer, we guide the referral to the right place, and to a urologist when a stone is large, isn't moving or keeps coming back.
If it's a small stone
Many small stones pass on their own over days or weeks. In the meantime, the medical team explains how to handle the pain, how much fluid to drink and what to watch for. One practical tip: pee through a strainer or a piece of gauze to catch the stone when it comes out, and bring it to your next visit. Knowing what it's made of helps prevent the next one.
Preventing the next stone in Houston heat
In Alief and southwest Houston, the muggy heat makes you sweat more than you realize, and concentrated urine makes it easier for crystals to form. A few simple habits:
- Keep a water bottle at work and refill it several times a day; your urine should look pale, not dark yellow.
- Cut back on the salt in deli meats, instant noodles and fast food.
- Don't cut out calcium-rich foods on your own. Ask first, because they often help more than they hurt.
Men get kidney stones more often than women. If you've had one, make it part of your men's health checkups. For prostate or bladder concerns, see our guide to urology care in Spanish.
Finding us
Clínica Hispana Cruz 4 is at 10100 Beechnut St Ste 240, Houston, TX 77072, with free parking. Walk in, or call (281) 588-0033 to set up a visit. If your side pain comes with fever, chills or vomiting, skip the clinic and go straight to the ER.
Need medical attention?
We're here to help. Call now to schedule your appointment or visit our clinic without an appointment.
Call now: +1 (281) 588-0033
