Lump on my side

So I noticed yesterday morning there is a small bean shaped lump/knot on my side roughly 4 inches below the middle of my armpit and it’s in line with my nipple which of course made me start thinking. It is very sore and I definitely have tried to not mess with it other than to make sure it isn’t growing. I know I haven’t hit it on anything it’s an awkward spot to even hit and I definitely haven’t taken any crazy falls recently 😅 I am planning to call the dr in the morning and see if he thinks I need to get it checked out. I guess I just wanted to see if anyone’s had anything similar