Hi
I'm Dr Nitish, MD
Knee pain as described by you is most probably due to stress on your ligaments because of weight. Arthritis at your age is very uncommon.
The pain running down your thigh looks like a pulled muscle, not a nerve. It may be nerve related but you haven't described any symptoms like that.
This needs to be properly examined for assessment, only scans and reports may lead to false diagnoses.
Next Steps
MRI of spine and knees, bone density and
vitamin d levels should be checked
Health Tips
loose weight, don't get involved in activities requiring running or jumping, weight training or yoga is ok