What Causes Swelling And Pain In The Calf Muscle?

My 56 yr old husband who has A-fib, is on coumadin and INR is in therapeutic range, struck his left calf on a lawn chair about ?5 days ago, and is now complaining of pain. (we were at a concert last night, and he was standing a for a few hours). It is NOT warm, no redness. The left calf is swollen, it was about 1 inch larger than right last night. He has been off his feet today, sitting in recliner, and ice pack to injured calf intermittently. No SOB, no Chest pain. I am an RN, and fairly confident it is a muscle injury, or ? tendinitis. We will see his reg MD tomorrow, but thot I would ask your opinion about waiting until tomorrow am. Onset of pain was last evening. He says it feels better now that he has been imobile, and ice packs.