When on cycle your nips get and constantly stay hard. Rubbing on your shirt can make them sensitive. This is a great learning experience for you, and I'd keep notes ed so you can refer back to them in the future. This is part of the process of learning how you personally are affected by aas. This is why test only cycles are recommended for first timers, and never add more than one previously unused compound per cycle. Keep us updated because this will be a learning experience for someone else in the future.
Also don't panic. Gyno is a process over time, so you won't wake up tomorrow morning needing to go get a pushup bra from Victoria's Secret lol