Fourth toe tucking under third and always very painful.

My toes are like that, too.
They've fallen sideways and gone triangular over the years, as they are undet the adjacent toe.

Sometimes I'm very aware that I've a big old lump of a woman standing on them, too.

Yes mine is triangular and the nail touches the ground (inside the shoe). My current chiropodist suggested trying to see a consultant in the local private hospital, but I’m put off by the thought of the cost, and I don’t think I’d have surgery at eighty three.

I have a stretchy cap I bought from Amazon that stops my bent over toe rubbing on the ground. It helps a bit.

Fourth toe tucking under third and always very painful
- I'm not sure what this means exactly as my 4th toes aren't really big enough to tuck under my third ones...

I can cross my big toe over the next one but the others (even with arthritis) seem to stay in a row...

Are your toes very long maybe?

I'm sorry you have painful feet though.

My fourth toe leans over and covers part of my big toe to the extent that the big toenail is being pushed down..
Hospital doesn’t want to do anything about it 🤷‍♀️