My 10 mth old wont sleep HELP?

I've taken him to the doctor several times (she finds nothing wrong). Ive tried the crying it out method, that doesn't work. He was on a perfect schedule until about 2 mths ago and its just got progressivly worse. He maybe sleeps 3 or 4 hrs a night and thats only if he is in bed with me. Does anyone have any suggestions? Im a first time mother