I'm a 38 yr old male who is in otherwise very good health. For the last 5 years I've been suffering from an illness that no neuro or rheumy has been able to diagnose thus far.

Here is the problem: I can walk say 10 blocks then head back home and there's no problem, but say that I were to walk 20 blocks then I'm likely to trigger a flare up. The flare up will not come right away, in fact I won't start feeling it until the day after next. So if I walk 20 blocks on a Monday, my flare will start on the Wednesday. Nothing seems to be able to stop the flare up from coming. The flare up will usually last about 5 or 6 days.

What I refer to as a flare up consists of the following:

Burning and tingling muscles all over my body on both sides equally.
Very tender and achy muscles.
Whole body fatigue (generalized weakness) probably from the pain.

I'm usually bedridden while I wait out the flare up. For DOMS they suggest against staying in bed however further activity seems to aggravate my symptoms. When I'm not flared up my energy levels are decent and I feel fine besides some myofacial pain from having been mostly inactive for 5 years.

Initially I thought that I might have a myopathy as my CK was measured at 10,000 however that was post-workout after a long absence from the gym and since then my CK levels have always tested within normal limits (was tested immediately after biking).

Spinal MRI, EMG and nerve conduction tests and a needle biopsy all revealed nothing.

As far as bloodwork my RF, ANA, IGam, ESR and CRP were all negative or normal.

I should point out however that I have never been tested (blood or otherwise) during an actual flare up.

So far I have been unable to find a Doctor that has any idea what is going on nor have I been able to find another single person that suffers from something like this despite extensive searching on-line.

This mystery ailment has robbed me of my livelyhood and I have no clue what it is. I don't understand why such mild exertion triggers these changes in my body. I've tried graded exercise but I never seem to get anywhere.

I see now that myopathy was a dead end. Given the burning and tingling aspects of this condition I'm thinking along the lines of a neuropathy but I don't have enough expertise in this area. This ailment started after about a year of inactivity due to suffering a burnout at work so I also wonder if it could be some kind of deconditioning syndrome. Some kind of auto-immune disorder seems possible although that's not hinted at in my blood-work.

I would be so grateful if someone knowledgeable would give me their thoughts or some advice. Thank you kindly.