If you push a workout a little harder than usual, some muscle soreness afterward is normal. That soreness has a real name, delayed onset muscle soreness, or DOMS, and it is not the same thing as an injury. Confusing the two matters because continuing to train through ordinary soreness is usually fine, but continuing to train through an actual injury can make that injury worse. The two can feel similar at first, so it helps to know exactly what separates them.
Timing
Delayed onset muscle soreness rarely shows up right away. Most people notice it 24 to 48 hours after a tough session, though it can start as early as a couple of hours afterward in some cases. If discomfort shows up while you are still working out, or in the first hour or two after you finish, that is not typical of DOMS. Pain that starts during the activity itself, or right as it happens, points toward an actual injury instead.
Character and Intensity
Ordinary soreness feels like tightness, stiffness, and a dull ache. It is usually tender to the touch but does not produce sharp or stabbing sensations. It also tends to show up evenly on both sides of the body if you worked both sides, both quads or both shoulders rather than just one. A sudden sharp, stabbing, or tearing feeling during movement is not how soreness presents. That kind of pain points to damage in a muscle, tendon, or ligament.
Duration
Soreness is self limited. It typically eases within 3 to 5 days, occasionally lingering closer to a week in more intense cases, and it gradually improves the whole time rather than getting worse. Pain that persists beyond that window, or that gets worse instead of better as the days pass, is more likely to be an injury and worth having checked.
Location
Soreness settles into the meaty part of a muscle group, such as the quads, calves, or biceps, not into a joint. Pain that shows up in a joint, in a tendon near a joint such as the achilles, the elbow, or the front of the knee, or in a hand or foot, is not typical of DOMS. Joint pain in particular is one of the clearer signals that something beyond ordinary soreness is going on.
Responsiveness to Movement
Soreness tends to feel worst first thing in the morning or after sitting still for a while, then loosens once you warm the muscle back up. A light, easy workout or some gentle movement generally makes it feel better, which is why most people with DOMS can still do a modified session. An injury behaves the opposite way. It does not improve with warming up, and pushing through another workout on top of it usually makes the pain worse rather than better.
Treatment
Soreness generally resolves on its own. Light exercise, gentle stretching, and a bit of patience are usually all it needs, and there is limited evidence that anything speeds the process up much beyond that. An actual injury calls for rest, ice, compression, and elevation, and for stepping back from the activity that caused it rather than working through it. If the pain does not start improving within about 48 hours, or it comes with swelling, bruising, or pain that wakes you up at night, it is worth getting checked out. Severe muscle pain paired with muscles that feel hard and swollen, or with dark, cola colored urine, needs emergency care rather than home treatment, since that combination can signal a rare but serious complication.
The Bottom Line
Soreness is delayed, dull, spread across a muscle group, symmetric, and it eases as you move and fades within days on its own. An injury tends to announce itself immediately or with a sharp, localized pain, often in or near a joint, and it does not get better with warming up or another workout. Getting this distinction right matters more than it might seem. Training through soreness is usually harmless. Training through an injury rarely is.