Thanks for your question on Healthcare Magic. I can understand your concern. No, erythromycin will not help in chest pain. Erythromycin is an antibiotic. It is used four infection. You are having left sided chest pain with lightheadedness. So we should definitely rule out hypertension and other heart diseases. So better to consult doctor and get done 1. Blood pressure monitoring 2. Ecg 3. 2d echo 4. Stress test (trade mill test). If all these are normal then no need to worry for heart diseases. Sometimes simple musculoskeletal pain can be the cause. So take painkiller like ibuprofen. Apply warm water pad on affected areas. Don t worry, you will be alright, but first rule out heart diseases and please don t take erythromycin. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.