He seems worse than before. When you crated him, was he on something soft, or was he standing on the bottom of a wire cage? Sorry, I know that seems obvious, have to ask. If it was wire on the bottom and he was in there for four days, he could have bruised the bottoms of his feet badly.
Based on what Ive experienced, he's hurt himself. I think the bruising theory is as good a theory as any. Also, it could be something not very serious, but his pain tolerance is low, then combine it with him being energetic and he thinks its all not good. I have a hen with a small bumble on her foot, she's been to the vet about it, its incredibly superficial, but by god you would think her toenails were torn out. The vet gave the hen hen ibuprofen to make her happier, ugh.
I would think about keeping him on a really soft surface if you havent already and see if it improves. Another option is to wrap his foot up with a big bunch of padded cotton on the bottom and see if he decides its more comfortable to walk on. Although that could be problematic in itself if there is something else on the foot compromised.
Have you been giving him aspirin?