What is causing for my right leg and shoulder to swell? this happens every few months. it is tiring to walk sometimes.

Unrelated: Your symptoms are most probably due to two different problems. Swelling of an extremity is often due to fluid retention(edema). Intermittent swelling of a shoulder is an unusual complaint. Unfortunately not enough information is present to give any meaningful advice. If concerned arrange to have an exam at a time when the shoulder seems swollen. Sorry I couldn't be more helpful.