It prob hurts because you have over used the muscle just take it as easy as poss for couple days you can do light jobs and gradually increase wat ur doing, but avoid heavy lifting as much as poss, I have 4 children and was on my own and had my 1 year old back from day 3 I was just as careful as I could be only lifting wen needed keeping my upper arms close to my side and tryed using my legs to lift xx