50yr male hypertensive having joints pain n swelling in one feet uric acid level 6.4, cholesterol normal , further investigation n what is the cause?

Sounds like: Gout. Gout is a form of arthritis associated with increased uric acid. It was famously associated with british indian army colonels who drank a lot of port wine. This is loaded with sugar and i believe that sugar alone can cause gout. Treatment is usually easy by getting Allopurinol from your doctor, but don't forget the potential long term prevention.