My 4.5 year old lab mix was out in the yard with me today and I noticed a large lump on the backside of her. It is slightly smaller than a plum, very hard, and seems to cause her pain when I touch it. My dog is with me nearly every minute of the day so I am extremely frustrated that I didn't notice this! She has been having some stiffness over the past 6 months or so to the point where I asked my vet about hip dysplasia. I wasnt allowed to go inside with her for the appointment per their covid rules so I'm wondering if they skimmed over her quickly and gave her her shots without really checking her over. Anyway, with my vet being closed until monday, I'm wondering if anyone can give a reasonable guess about how serious this could be? I understand that testing is necessary, but until that can be done I'm just looking for reasonable possibilities