Experiencing dull discomfort on calf, shin, inner thigh that comes and goes. sitting too long also causes pain on mid-thigh muscle. all on r leg only.

Stretch frequently: you need to be careful and often get up and stretch and walk sitting for too long will make you a candidate for deep vein thrombosis which could be dangerous and life threatening take ibuprofen for the pain wear a support stocking if you can and again stretch frequently

Swelling on R leg?: Hi. Have you had any injury to the right leg, surgery, or prolonged travel recently? Is there edema on the right leg? Is it better with elevation? Your symptoms are not specific, but could be explained by a blood clot. You should talk with your doc about this. With a better history and exam, she/he can best assess what might be the cause and what further to do. Good luck!

Nerve.: Although it could be a possible vein or clot in vein problem, I'm more inclined to think is has something to do with your lower back and the nerves running down the leg. You might consult with a specialist for a definitive opinion.