I m getting tight chest pains and its causing me to have breathing difficulty and it hurts to take a deep breath. could this be a pulled chest muscle?

Possibly: This could be simple or very complex. Due to the fact that you are only 18, it is more likely that this is not an emergency, however, it could be more than simply a pulled muscle and with this amount of limited information, i think it wise to go be checked out to play it safe as there are other things more serious to worry about here. Don't panic, just play it safe please.