So I've been playing guitar for 10 years now. I have always played primarily acoustic. I play at least an hour every day so I know my guitar muscles are pretty ripped

I know my Martin d-28 with medium strings does not help the situation. But I have a lot of trouble with thumb/hand pains, especially with barre chords. Sometimes the pain will even creep up my forearm a bit. The pain usually kicks in in the middle of a song that uses barre chords. Using light strings does help a bit but not much. I know I could switch to a taylor or something with a smaller neck but I don't wanna!! I love my martin. Also, I have very average sized hands.

Anyone have similar experiences where you are a long time player and still have similar troubles?

Any help or suggestions greatly appreciated
You should go to a doctor, my band bass player was having a similar issue, the doctor tell him that he have to use wristband for two weeks, now he is better!
Good Luck!

Ibanez RG7321
Ibanez GSA60
Jackson RR3
Guitarra Acustica Vicente Tatay 1969
Line 6 SpiderIII 75
Digitech MetalMaster
Digitech Blues
Dunlop WahWah Dimebag pedal
Some generic Johnson bass and amp
Zoom 101 Multi effects
hmmm interesting...

my father happens to be the type of doctor I would need to see. And if I ask him he will tell me to quit playing guitar!

so I think I'll get a second opinion
I've got the same problem.
I had some relief after I started doing taking warm up excercises and stretches more seriously.
You could also try eating some joint supplements.
i had the same problem when playing narrower necked guitars or certain shapes of necks.

this can be a serious problem that leads to surgery and the inability to play. maybe ever. my left hand and arm were messed up for months. it can be repetitive motion disorder, carpel tunnel, tendinitis or a variety of other issues. i know we hear the term "carpal tunnel" a lot, but make no mistake, this is in reality a very serious issue.

i STRONGLY recommend you go to see a doctor - a specialist, not a gp or your family doctor, who won't know anything. if you absolutely won't go to a doctor, better try lighter strings and see what happens - or even try extra lights for a week and see if the pain goes completely away. if it does, better kiss those mediums goodbye, start tuning down a full step or using a shorter scale guitar asap.

and don't keep playing through pain or you may never be able to play again.
I used to have a similar problem with my thumb. Hurt a lot when I played barre chords, but then I realised my thumb was double-jointed.
I had to correct this basically, by changing where I put my thumb on the neck. Took a long time, but the pain's gone now
Where did you end up putting your thumb. I think my thumb is double jointed and i do have pain after a while of barre chords