Apply ice pack and put a towel roll under knee and press for 10 second then release repeat 10 to 15 times if it work then OK otherwise physiotherapy treatment must

Bursitis? Confirm with c-reactive protein and erythrocyte sedimentation rate and complete blood count and X-ray knee AP and lateral views

Bursa is a shock absorbing material . You need to go for investigation first like usg,ct .if the suspected diagnosis confirms then pls apply cryotherapy & creep bandage along with anti inflamatory drugs suggested by your MD.when the pain & swelling subsides upto 50% ,pls go with regular quadriceps & hamstrings exercises for further recovery.A qualified physiotherapist will surly guide you properly to prevent father reoccurance.

If it is in front of the knee - it is called prepatellar bursitis. If it is swollen and redness there you will benefit from antibiotics. If you doing any job involving kneeling wear some knee protection. Consult Ortho Doctor