Hello, I Have A Pain On The Crease Of My

Hello, I have a pain on the crease of my arm, where one would normally have their blood drawn from. I've had it for two weeks now. The pain radiates to the elbow area. It is a very bothersome constant pain. Today I noticed a little inflamed lump in the area, like a mode. It is painful when I press on it. What I'm concerned about is that for about the same amount of time I've had another node under the armpit that has been hurting as well. I've had an ultrasound done for this one before because it comes and goes, but nothing was detected. Should I be concerned?