That could suggest a reaction to something he's stood on. Even if the vet finds nothing, it might be possible to give him a non-sedating antihistamine and see if he gets better (I say non-sedating because if he's sedated he might seem calmer anyway). If it seems to make a difference then you've narrowed down the problem. There is a 'human' OTC antihistamine in the UK that is safe for dogs, but I think it may be sedating, so you'd have to ask your vet.
Or you could try a soothing foot bath. There's a web page about itchy paws & remedies here, though I can't vouch for its reliability: http://www.limitlesspawsibilities.com/Going_Essential/Entries/2016/4/26_Itchy_Paws_101.html
And more here: http://www.dogsnaturallymagazine.com/aromatherapy-allergy-relief-itchy-dogs/
Another fresh example:the normal play of every night today was like he was on cocaine or something.... it's like he is his normal self but with hyper reactions... strange...