Which tests should I undergo for swelling on my feet?

I am a 66 years old male underwent blood test, which showed globulin - 4.1 gm/dl, total acid phosphatise – 8.9 U/L and ESR - 57 mm/hr. All other parameters fall within the normal range. Sitting down for long durations make both my feet swell considerably though the right leg swells more than the left leg; but vanishes by morning. I take Hybesor (20mg) and Felogard (10mg). Sometimes, I develop slight fever and have a heavy head. I also take medicines for high blood pressure, which is under control.