To make changes in your strength, you do need to push yourself, and you might experience delayed onset muscle soreness, aka DOMS. This type of muscular pain means you challenged your muscles, and it comes on after a workout. Here are a few ways to prevent the hurt after the burn.
However, if you feel a sharp, shooting pain, especially in a joint or your lower back, this means stop and check your technique. Try the motion again a little more slowly and thoughtfully. Same pain? Then try the motion smaller. Same pain? Stop. You experimented with your options, so stopping does not mean wimping out.