I am only 18 years old. My left breast has been experiencing some sharp pains only at night when I'm laying down or just sitting there. Its been going on for about 2 weeks now. I don't know what it could be and I'm scared. I would go to the doctors but I have no type of insures right now. I have my boyfriend check my heart beat every day and night and he says it always feels normal. Also The pain some times go to right under my collar bone. What can it be?