Can I go to church/worship during chemotherapy treatments?

Yes. We generally tell patients to stay out of situations where there are crowds, young children and people you do not know. Of course religious venues contain most of the above. We tell patients to arrive right before the service, sit in the back and leave immediatley after the conclusion. You want to avoid well-wishers. Also wearing a face mask is a good idea - they think twice before coming close!
Chemo. There are many different kinds of chemo. They lower immunity and in some cases it's best not to be around crowds. Please ask your doctor if this is the case in your situation. Peace and good health.