Riding in a Connie combs clinic in a few days and everyone at the barn had to do mandatory spring shots..my guy is very sore and grumpy..I rubbed DIO liniment on yesterday..but under saddle is grouchy..What else can I do to combat the soreness? In 8 months of owning him he has never been grouchy under saddle   and I’m paying $400+ for this clinic..would bute help? 

Bute should help with the swelling and soreness but the best thing I would do would be to make sure he is turned out and moving.

The grouchy under saddle could be from many other things besides shots.... 

Yes, he’s outside 24/7..

he could have had an off day under saddle as well. 

I wouldn't stress over it. 

Light exercise and dmso rubbed on the injection site will help.

Thank you! Will stop at TSC on my way to the barn this morning. Will I need gloves?

Yes, definitely use gloves :-)

For shot reactions, my vet always tells me to use BANAMINE over bute. Banamine is better for soft tissue/Muscle soreness. Bute is better for boney type soreness. Banamine also reduces fever ( That might happen after vaccination) as well , way better than bute. But yes bute will take pain and swelling out. Banamine is just better. I have one horse that always has a reaction to vaccines and my vet has me give him a dose of banamine at the same time and even next couple days if needed. 

Thank you all, rode him lightly this afternoon and he was feeling a bit better! I have the vet coming out Monday morning for chiro and will grab banamine to have on hand. 

Honest to gosh best place for yearly vaccinations is in the pec muscle. Most horses won't even notice the poke. My vet agrees as we started it as a precaution on my show horse. Last thing I needed was a swollen neck. If they do have soreness in the pec, they can still eat and drink and move around normal vs if their neck is sore.

I have one that gets like this. She is also out 24/7. It's annoying and can be alarming but a little bute for a few days does wonders.