my cat has been chocking/gaging

[ginamariejulia]

My cat has recently starting chocking/gaging for approx 1 min each occurance and this happens 3-4 times each day. I took him to the vet and bloodwork and xrays came back fine. I have even tried changing his food and this has not worked. Sometimes when you pick him up it will make the chocking start back up. My cat is 6 years old and has never done anything like this before. Any advice?? Thank you.