My cat has intermittent lumps on his back

[user1471867483]

When I stroke him and towards the end of his back he has what I can feel are lumps. They're not particularly along his spine but sporadic around it/sides too. He's the most difficult cat to examine as he'll run off if I take more than a few seconds to touch him, but I've felt these lumps for the past couple of weeks. His appetite is fine as is his toilet functions. He's 14 years old btw. I just wondered if anyone might know what my vague description might be? He also has quite a dandruff-y, greasy back too. When I stroke his back area his skin twitches.
Thank you in advance.

[trythisforsize]

Take your cat to the vet.