Sore arm after chemo

I'm on AC chemo and had a similar experience after my second dose, although it was not an immediate effect but occurred several days later. My arm was tender and I had slight swelling in the inside of the elbow. My oncologist said chemo had irritated the vein. Next time I had chemo the nurses went for a vein that didn't flow into the irritated one so all was good and the tenderness subsided. However it's always good to get these things checked. If you don't want to call your oncologist in the first instance you could always touch base with your breast care nurse. And never worry about being a wuss when you have concerns!