Lump and pain in lower back

Hi

I was just wondering if anybody has experienced lower back pain, with a lump?
My brother has had lower back pain for a couple of weeks, he does have a physical job so probably not surprising, but now he can feel a lump in his lower back. It’s just above his buttocks. I’ve not felt it but he says he can feel it especially when he’s lying down and it’s only on one side.
Of course, my mind goes straight to the worst case scenario. He says he is going to the GP to get it checked, but in the meantime, has anybody experienced symptoms like this and it didn’t turn out to be something sinister?

Thanks

Are you sure this isnt a bone?

I hope he already has answers. I do have a lump on my lower back which I had scanned and is a lipoma, which can get painful because is quite big and deep inside, although completely harmless. I hope everything works out x