This treatment is being suggested on bases of the information provided. However I would like to examine & investigate you  in detail. -Control  Hypertension, Diabetes or  metabolic disorder, if there is any. -Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. -(You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Use no pillow under the head. --. Avoid painful acts & activities. -- .Do mild exercises for the affected part-ie. Back and lower limbs. --.(Take help of physiotherapist or you can visit my YouTube channel Dr. N. C. Gupta and watch 'Me & My Yoga' and 'Yoga Simplified'. --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment visit nearest hospital. --Wish you a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.  Dr N C Gupta MS (ortho)

At your age most common cause of pain is Chondromalacia Patella( Softening of cartilage underneath the knee cap).

Could be due to patellofemoral pain Need to see physiotherapist to help you with stretching and knee strengthening exercises