Having problems with my 8 month old?

So lately my son has been crying a lot! When I make him his bottle of 7oz he only eats maybe half of it and then wants nothing to do with it. Then just a few hours later hes crying more he hasn't wanted his pacifier at all I've tried to give him a nap and he fights it I just don't know what is wrong with him and why he is being this way. He isn't sick no runny nose, cough, fever nothing I see on the outside.