Do i need wear arm sling if have rotator cuff injury and shoulder strain? is safe take ibuprofen or aleve (naproxen) with diclofenac 75mg?

Ask the Dr: The Dr who diagnosed the injury is the best to ask for recommendations specific to your case - but it's worth trying the sling to see if the protection it provides reduces your pain. The medications you mention do not have reports of problems in combo, so just use as directed and notice anything you don't like. I hope you heal well. See Dr if worsens or lasts too long (weeks).