Suggest Treatment For Right Nipple Pain

Im male, 20, small build(around 5'11'', 155-160 lbs) I am having slight-medium pains in my right nipple. Never had this problem before, and it does not exist in my left nipple. It only hurts when pressure is applied to it(for example if im laying down on my stomach and am leaning to my right side). I feel no lumps at all, no irregularities. I see no bruising. There is a slightly visible vein from the top of the nipple that leads upward and towards the center towards the neck. I have sustained no injuries that I know of around that area of the chest and I've had this pain for a little over a month now.