Model Issue

I’ve run into a small problem while trying to model my character, I started with a cube, sub divided and then cut it in half and removed the side by deleting the faces. I then proceeded to model my character, I checked the subsurf modifier and this is what it looks like.
Not sure what I did wrong. Can anyone help me?

Sure we can help but it is hard to see what is happening, just post the blend. It looks like you have faces inside your model, delete them!