My cat Squeek! is eleven or twelve years old. The other day, my roommate discovered a softish lump on his chest, confirmed by a friend of ours. When I got home from work, I could find no lump, and the next morning, neither could my roommate. Fast forward a couple of days, and now his right arm is slightly swollen. He does not seem to be in any discomfort and is acting normally. I want to observe him over the weekend before calling the veterinarian, because, honestly, I have no clue what to tell her...Anyone ever seen something like this?