lump in breast

So today I found a lump in my right breast about the size of a pea, it's hard and kinda of painful. (I have a dr Apt soon) but just wanted some opinions or know if anyone has ever had the same thing. I've read that if it's painful it's not cancerous but you can't really go by everything you read on the Internet. I'm only 19 and was told it's very uncommon for breast cancer at this age. Some please help me stop stressing myself out.