I have been taking cipro (ciprofloxacin) and Flagyl for about 48 hours for diverticulitis I am now having shoulder pain I researched and it appears I should stop the cipro (ciprofloxacin) r t tendonitis et al can I continue with just the flagyl?

No. Shoulder discomfort is likely not related to the antibiotics. Keep taking the antibiotics as prescribed & contact your prescribing doctor for an examination. Do not stop medications without discussing with your doctor.
Go back to doctor. Although Cipro (ciprofloxacin)floxacin can create tendon problems it is entirely possible that the shoulder pain is related to diaphragmatic irritation from problems related to the diverticulitis. The actual frequency with which Cipro (ciprofloxacin) creates tendon issues is very very low. Please go back and see your doctor.