Although he may not feel much like eating when his gums are aching, the little guy can still find relief from foods if they're very cold. If solid foods are a part of his repertoire, try feeding him something soft and soothing like applesauce or yogurt. You could try an ice pop (made from fruit with no sugar added) or frozen yogurt pop. Some parents put formula or breast milk into ice pop molds to create a slushy treat. You might prefer this if you're not ready to give your baby fruit or dairy just yet.
On the other side of the coin, you might try giving baby some cold, hard foods to gnaw upon. Carrots or apple slices from the fridge are all common offerings. Occasionally parents will give frozen foods like bananas, bagels or french fries. Typically large pieces of food are only given to babies who don't yet have any teeth because that means that the likelihood of them able to bite off anything big enough to choke on is low. However, you still need to supervise him very carefully if you decide to give him any of these foods.
Your baby may not be into chewing on something cold. Next up: lots of other things made for gnawing ... and some that aren't.