My doc says i have a loose knee cap, it can be really painful at times. i'm 22. what can i do to make it better?

Exercise: Strengthening your quadriceps and stretching your hamstrings can help to reduce knee pain. Avoid the leg extension machine at the gym. Walking on a flat, level surface, riding a bicycle, using an elliptical trainer and some standing yoga poses can all help strength and reduce pain over time. If needed a soft knee brace with a hole for the kneecap can sometimes help during activity.