Sharp constant pain around left ribcage, hard to breathe normally. what could be wrong?

Need history/exam: Details about your age, whether you are male, or female, family history, whether you smoke...All comes into formulating an educated guess. If you had a history of osteoporosis, a fall, or excessive coughing... It would make the guess easier. But a guess is all it would be. An evaluation is what is best, especially since your breathing is compromised. You need a definitive treatment.