I can understand your pain as this was the issue of knee joint. Knee joint is a very complex joint which has many structures. So injury to any structure, radiates pain to surrounding areas. I had seen such cases even before in my clinic.
There are different causes of
knee pain like tendon injuries, menisci injuries, ligament injuries,
arthritis, gout, SLE etc.
As pain was radiating to thigh the most probable cause might be ligament or
tendon inflammation. That can be confirmed by investigations.
Best method to know the condition is
1. X-ray
2. MRI of knee joint
3.
blood test to check any infection
Coming to treatment part you have to follow the below:
1. non steroidal anti inflammatory drug (
ibuprofen)
2. ice compression and elevation of leg
3. steroid injections if pain is seseve
4. reduction of weight is advised
Hope you will act according to the above and recover soon