Hello there,,,,well joint pain can be due to various reasons can range from as simple as a overstrain muscular pain or can even be a bit complex like Arthritis,,,also you mentioned the knee joints pain the most....well a clinical examination along with xray and
calcium levels need to be checked...inorder to have a proper diagnosis.
Next Steps
get both leg xrays in AP,Lat and sunrize view
get CBC,Sr
calcium,Vit D,sr
uric acid,RA factor tested.
Health Tips
You can visit an orthopaedic surgeon or a musculoskeletal Physio with the above reports.
do resort back to me regarding any furthur queries.
Take care.