The hardest time is when our pets get old. How much treatment to try or let the dog decide. We just lost our 12 year old dog 2 months ago. It only started with limping and after 2 weeks we
took him to the vet. He gave us medication for 1 week and then
he did a x-ray since there was no progress. There were several spots on the x-ray and we found he had aggressive bone cancer.
We gave him pain medication, spoiled him with fresh organic hamburger and he died 2 weeks later, still happy but could not walk anymore. Very hard on us but we felt good that he did not have to suffer anymore.
Your vet should at least have done an x-ray there is good chance
that the mass is cancer. A lot of dogs get cancer now a days, even at young ages.
Dogs know when their time is up, if they were free roaming
they would hide in the woods stop eating and drinking and die there, that is what my friend's dog did.
You have my best wishes, these times are not easy we have gone through it several times, but first of all make your dog comfortable and may be you could get something for his pain.