Hello Erin…..you need to take him to the Vet. Urinating suddenly like this could be sign there something wrong…kidneys, crystals a bladder infection…all sorts of things. Take a urine sample with you if you possibly can, it will help the Vet pinpoint the problem.
Hope he recovers soon!
Unfortunately, it is very difficult to tell from the picture exactly what type of mass is growing on your dog. What I can tell you is going to be evaluated by your vet is the best idea and I’m very happy you have an appointment. Also, at 2 years of age it becomes less likely that the mass is some type of cancer. Likely unless it’s a parasite or cyst your vet will likely recommend removal and sending the mass to a pathologist to determine the type of mass.
Good luck! I hope everything works out for your dog!