Right knee pain on inner side of knee cap can't bear weight on it unless its straight but when not bearing weight i can't straighten it.

See below: Could be something wrong with the medial of your right knee such as oa, meniscal tear/ligament tear. You may need imaging to better determine what is going on.

Meniscus tear: Pain on the inside (inner side) of the knee can be from a meniscus tear. You could have some knee cap arthritis, but unless severe it usually doesn't limit your knee motion. I would get and evaluation by an orthopedic specialist.

Knee pain: In addition to a possible meniscus tear as suggested by the other physician previously, patella-femoral pain syndrome, retropatellar pain syndrome, chondromalacia patella, and runner's knee. The pain associated with this problem is often described as a locking sensation when the knee cap does not track properly in the groove that it sits in called the trochlea. Ultimately, this does need to be further evaluated by an orthopedic surgeon to help figure out the problem and recommend proper treatment.