[HappyDog]

My Alfie is over two years old, he'll be three in March.
He's been vaccinated for kennel cough and yet I've noticed that after physical activity he hacks and coughs for quite a while. We use a harness on him, rather than a collar because we thought that was the problem (he's been doing that since he was a puppy) but it doesn't really help anything, he still coughs after a walk.
He occasionally will throw up yellow bile. We read somewhere that that's because he's hungry but our vet told us that's not the case, they don't throw up bile when they're hungry, but our vet also told us he seemed healthy and nothing was wrong, yet he still occasionally throws up. Every time he does we make him a special meal he won't be able to resist (mix mushed food with his hard kibble or make a homecooked doggie-safe meal) and afterwards he's fine.
The past couple of days however he's been refusing all food. I've had to force feed him a couple of meals and less than an hour later he coughs it back up.
His eyes are sometime runny and he seems somewhat lathargic although he still will play, go outside and run on walks.
Really don't know what's going on with him.
Anyone have ideas?