Itching

My little buddy is about a year and a half old, and has started itching a whole lot roughly 2 weeks ago. It’s mainly his belly, under his front arms, and he licks his paws quite a bit. I cannot figure out what is causing it. He has been on the same food for quite some time, but about a week ago, I switched his food to the lamb and rice from the chicken and rice to see if that would help. So far, it does not seem to have helped.

I’ve been giving him Zyrtec and Benadryl(not at the same time), and also have some antiseptic itch spray I’ve been using, but that seems to only slightly temporarily help. I also put some A&D ointment on the spot on his belly.

Any help or advice would be greatly appreciated, as I cannot really afford a huge vet bill right now.