The pain you describe sounds very much like pain of the chest wall that includes the ribs, muscles, cartilage, intercostal ligaments and nerves. That is it does not sound like pain from the pleura, lung or any of the underlying organs.
The new class of drugs was known as beta-lactamase inhibitors and they worked to block the ability of the S. aureus bacteria to destroy the distinctive penicillin ring structure. The new combination drugs that are effective against Staphylococcus aureus infections are amoxicillin/clauvulante, ampicillin/sublactam, piperacillin/tazobactam and ticarcillin/clavulanate.
These antibiotics are much better than TMP-SMX for strep infections. These drugs are also safer than clindamycin, for widespread use. Clindamycin and TMP-SMX drugs should be reserved for abscesses or draining wounds with a high likelihood of MRSA, not used for every uncomplicated skin infection.