I'm shocked you started chemo that quickly. ..I was made to wait 6 weeks. Anyways with each round of AC my mastectony scars would ache and feel tighter. When I told my team they scratched their heads. Eventually, at my suggestion, they realised I was getting trunkal oedema that was most likeky due to the steroid withdrawal. It resolved prior to each chemo. I wore a variety of different bras....sone aaaah type ones or erilan clip up or sometimes none ...depending on the day which felt right. A shapewear singlet helped. Also is the picc line on your node removal side?. I found I also got tightness between elbow and wrist on this side which was cording...but worsened after chemo then would improve. Tell your team. They may have ideas. Take care. Chemo as well as mastectomy is hard. You have rvery reason to feel miserable. But 2 more AC to go. Taxol is different. I still got the tightness though. Kath x