My dog has a lump on the top of his tail?

My dog is 5 months old now, and over the past two days I have noticed that he has a hard lump on the top of his tail, I have noticed that he hasn't been wagging his tail as much, and if he does- he wags his tail below the bump, but there is no movement above the lump, I have tried lifting his tail, but he squeals quiet loudly, and growls if I try now. Can anyone help me or suggest what it may be!?

Go to a vet and have them examine it. It may be a tumor.

Hey!!There are many possibilities as to what the bump at the end of his tail might be. It could be a sore, maybe she got bit my something or scratched! Another possibility is that it could be a cyst. You should call your vet, and have that checked out, just to make sure it's nothing serious. Don't worry, if it is a cyst, it can be easily removed with surgery.It could also be an infection! Think: Has he been anywhere "new" or "strange" lately? Has he eaten something he's not supposed to?Finally, the last possibility as to what it is, is possibly a tumor. It could be a cancerous tumor, and I would get this checked out as well.Hope I Helped, And I Hope Your Dog Feels Better!!-XOXO,Ariana