Weird scabs all over my kitties back

I don't know if this is the right place to post this but my sweet boy Westley is having some skin issues. I've had him for over a year and he only started having issues after I moved into my friends house (bc my housing situation was no longer available) and ive been living here with my cats since march and he started having the skin issues around early june or late may. But basically he has little scabs and rough spots on his back close to the base of his tail. When I pet him i scratch his butt and can feel all the lil scabs and im really concerned. I believe he is stress cleaning himself because when he is in my room he just licks and licks and licks and bites and licks until i finally get annoyed and stop him. I think being in this house with a lot of other cats (my friend has 12......) is stressing him out. Hes not afraid of the other cats though and he gets along pretty well with them, however when we rescued him he was a bit skittish and idk thats just his nature. 

tonight i was rubbing him and the scabs felt bad so as per a suggestion from my friends mom i got some castor oil and like tried to rub it through his fur onto his scabs (hes a long hair cat tho so it was kind of difficult) most of the oil ended up just being in his fur on top and it was also really sticky. (ive never used castor oil before and should have done research myself i know but my friends mom usually knows what shes talking about when it comes to cats) but anyway i dont think the castor oil did anything hes just licking it off right now which i read will make him have a bowel movement ?? 

id rather not take him to a vet for this bc they arent bleeding scabs and hes just over cleaning so i dont think the vet would give me anything except an e collar to stop himself from biting and licking. 

can anyone recommend oils that would work and not hurt him or get his fur sticky. i just want him to be happy and not nervous and stressed out cause i love him. anyone else have experience dealing wit a stress cleaning kitty? any help would be much appreciated 

@ToulousesMomma   I don't know of any oils that would work for scabs on Westley's skin.

Are you sure the scabs are not from flea bites, or allergies to either food, or something in the air/pollen etc.

The vet would be your best bet, since they could take a culture of the scabs and also recommend either something for allergies, fleas, coat conditioners or shampoos/creams.

It must be hard on your Westley being itchy all the time, so I hope you find out something that helps.

Even offering calming meds as a last resort, for nervous itching or stress might help.

If you think your vet would only offer an e-collar, then phone around and get other ideas and prices from various vets. They all seem to be different.