I soooo feel your pain! my 21 month old is not sleeping in his bed and when he sleeps with me, he tosses and turns. I've found that the more I wear him out (playtime... outside... activities) the better he sleeps. Also, an earlier naptime and waking up from the nap no later than 3 also helps a lot.
Sometimes, I have to make sure his tummy is full with a snack or such to help him sleep. OThers, it may be allergies, but I'd double check with your ped before doing that.
As far as the breast "smell", there is a little logic in that. Mostly it may be just your smell, not the breast milk. You may have to wean him because he simply isn't getting full at night anymore. AS hard as that is to do since you want to nurse longer, you may find that a full tummy at bedtime (ie: cereal, 1st foods) will make a world of difference. Your son may be deciding that he is ready to be weaned. All three of mine were weaned before a year old because they were ready for more solid foods and my milk just didn't fill them up anymore (lord knows I made enough).