After a hemorrhoidectamy, can you go back to lifting weights or will it cause a reoccurance? if not what about push/sit/pull ups instead are those ok?

Wait: I would wait at least 6 week before doing heavy lifting. You should speak with your surgeon to see what their recommendations are for activity after that. The biggest issue with recurrent hemorrhoids is straining at hard stool, so make sure you are increasing your fiber intake or using a stool softener like miralax (polyethylene glycol) daily to maintain toothpaste consistency stools.