Gyno can happen at strange times...there's still a lot to learn here. In my earlier days, I did heavy cycles of D-bol, Test, & Deca with no anti-estrogens what so ever. I never developed gyno and I paid very close attention to my body. After 6 cycles during a 2 year period, I decided to quit the juice. One year after my last cycle, gyno appeared in the form of a lump under my left nipple. I hadn't touched anything in one year! I was 20 years old and very scared, because I thought that it could have been a malignant tumor or something. I had a biopsy and they found it to me benign to my relief. He said that it was just hormone growth and nothing to worry about. In fact, he didn't even cut it all out because he wasn't worried about it at all.
Gyno can happen unexpectedly at various times, which my experience has proved. Soreness was never a symptom in my case. I just found a hard lump under the nipple.