I ALWAYS start my AI as soon as I start my cycle just to be careful. Maybe its not gyno, maybe it is. There is a post from Austinite around here that talks about Gyno and what you should do. If your nipples keep hurting and develop a little pea sized lump or something, Austinite's post recommended taking 40mg Nolva (Tamoxifen) a day until you're better. It is currently working for me, my left nipple isnt as sensitive and the lump is getting smaller. You gots some SERMs right?