Tingling in one breast

I have had tingling in my left breast and nipple for about two months now - and some pain sometimes but I think the pain is cyclical. Saw doc and she blamed it on stress and said she didn't know what it is. She found no lump. A couple days later the nipple inverted - but it came back out. U/S revealed no lump. No other symptoms. I am really stressed over this and looking for answers.