My 13 yr old choc lab has started pooping in his bed. Mainly when I come down in morning he's done it and hasn't even moved.
He also has done it around the house even though the garden door was open for him.
Is it his age or could he have a underlying problem? Help!

Yes at 13 he could have an underlying problem...
You need to get him to the vet for a full check-up, don't forget to take a stool sample with you. You can pick up specimen jars from chemists (pharmacys)