Left side chest pain that is worrying me, do I need to go back to the doctors?

Hi,

Lately, I've been having left side chest pain that can be anywhere between the top of my left chest to the bottom. It's normally a sort of ache but can occasionally be sharp. The pain often goes in the left side of my upper back and shoulders too, with occasional sharp pains in my neck.

I believe the pain also gets worse when moving around and it can make me feel breathless and uncomfortable.

I'm a 19 year old female and recently went to the doctors with similar symptoms. The doctor diagnosed it as costochondritis but I can't see how I could have gotten this and the pain is still worrying me, especially as because it is around my heart.

Any advice would be appreciated, thank you.

Do you get palpitations?

Sometimes, but it's rare

Do you take any medications like the contraceptive pill?

no, i don't take any medications 

Does the pain get worse after eating?