I am 17 years old and have a tissue mass on the lower left rib cage, it hurts every-time i breathe i haven't had any injuries or sicknesses reacently?

More information: Is the mass red? Warm to touch? How long has it been there? You really need to have a doctor LOOK at it and get some more information about the nature of this mass. Make an appointment to see your physician asap . Don't delay. It may be nothing, but the fact that it makes you hurt to take a deep breath, it can lead to other more problematic issues.