My (almost) 12 year old Beagle has bumps on her sides....?

not at all uncommon for old dogs to develop harmless fat tumors. They can be unsightly but unless they are in a pressure point area seldom ever cause discomfort. Most vets recommend leaving them alone unless they cause discomfort or get very large. You do need to have a vet look at it though just to make sure it isn't something else. Cushings disease does cause symptoms Yes tumors also noticeable increase in water intake, noticeably thinning of and often courser coat waning energy levels weight gain. It can be managed with treatment though. If your dog does have these symptons then having her seen by a new vet is exactly what I would do. I would never accept the answer this vet gave you.