External or internal ottitis. IE A ear infection. You need to make a vet appointment within 24 hours as this is accutely painful for your dog and can result in a ruptured ear drum and deafness.
If it is swollen on the inside, you need to see your vet. There could be an infection in the inner ear which needs medical attention. Other possibilities, ear mites, ear wax build up. I would just go see a vet to make sure there is nothing seriously wrong.
There could be any number of reasons, if your dogs ear pinnae are swollen and feel as "bouncy" as though they are filled with fluid, he could have aural hematomas, when the space inside the ear pinna fills with blood and fluid due to your dog scratching his ears excessively. This is not life threatening, but most likely quite uncomfortable, and is likely to recur if the cause of the itchiness remains untreated. It could also, however, be an abscess, which could potentially become life threatening and most definitely requires a visit to the vet.
If the inside of the ear appears red and swollen, it is often due to chronic ear infections and irritation, most commonly caused by Allergies. Some dogs have a predisposition to ear infections as well, Labrador Retrievers are at the top of that list. Any dog with floppy ears can be prone to getting ear infections. Here again, a visit to the vet is in order to get treatment for what is causing the irritation.
There are probably other reasons your dogs ears can be puffy, your question could cover a lot of territory, however, the ones I've listed above are common reasons for it.
There are a few things this could mean. One, your dog was attacked by another animal and their fight caused him to get a cut that got infected and is now full of puss. Still, if it doesn't go down, I advise a trip to the vet, just to make sure everything's alright.
If there is any thing swollen or if your dogs limping and wineing
boxer dogs
Boxer dogs. You better belive it.
of curse yes
You can separate the dogs when it's feeding time, like a separate room. Or, you can keep the dogs apart with a baby gate.
because you have a ear infection.
Because they're dogs...
They can be if you train them the right way.
allergy
A boxer dog is a jogger because it is a submissive dog.
Food
They have no predators