Boob problems lol

So my boobs just...hurt and I'm not sure why. Sometimes when I rub against something and my boobs hit it, they hurts really bad, sometimes when I'm lying on my stomach they hurt. I'm just scared of any diseases. My boobs look normal (when I look in the mirror) put when I touch them so see where t hurts, it's on the top and sometimes the sides. Please don't scare me in the comments, I just want help :(