Why my nipples are very sore

[notyap]

I had my period on 3rd july and finished on the 8th july, then on the 11th i had brown discharge, then on the 12th i had light red when wiped then i had light bleed when wiped on the 15th july and then i bled on the 17th july for that night but it wasn't heavy or anything and then on the 21st july my nipples started hurting real bad where as even a slight touch to them or having a shower and the water falls on them it really hurts, 26th July i had clear discharge like egg yolk and then nothing after that. I have taken 2 preg test and both have come back neg..I went doc on 27th july and that didnt help at all they reckon just wait until next month if i miss my period. I am wanting to know if anyone has had that problem with there nipples as today i played my rugby game and also during the game i got a pain in my abdomin and lower back like a period cramp but no bleeding or discharge, where coughing it hurt too but only lasted for maybe 10 - 15mins. Please help if you can lol