Can antibiotics (z-pack)lead to indigestion (last 3 days) and fullness on the right side (today) 1 week after i finished taking them?

Antibiotics and GI: Antibiotics attack the bacteria causing infections and normal friendly gut bacteria that help with digestion. It is common to have digestive symptoms with the use of antibiotics. You could try taking a pro-biotic supplement to replace the healthy bacteria. Also, avoid dairy products for a week. If not better after 7-10 days then you should get evaluated by your Family Physician.