Reply to Mia's Post: I don't lift weights. I'm not on any medications. There isn't a lump on the same area of the other arm. I don't have any health problems that I know of. The lump isn't painful, unless you were to push very hard on it. Even then the pain is fairly mild. I don't notice that it's there for the most part, unless I rub across it. It doesn't really protrude off the arm. There is no color to it. It almost feels like a circular\oval shaped knot at the top of the bicep muscle. I can feel a little pressure if any also in my arm pit and slightly at the front side of my body located on my mid shoulder. I lift small refrigerators at work, but I don't remember feeling any pain from that. Another thing is for a few nights I woke up to my left sleeve of my short sleeve t-shirt wrapped or squeezing kind of around my upper left arm and arm pit as if my shirt got tangled( it was a rather tight or smaller t-shirt than I normally wear). Just like an old t-shirt I wear to bed sometimes. I can't think of anything else that would cause this small bump. I've had it for about 3-4 days or less. It hasn't changed shape or size. I don't know if it is a bad knot, a cyst, or a swollen upper bicep muscle, lymph nodes, a tendon or what.