My case is kind of similar. All started around one day one and half years ago I walked about 18000 steps in preparation for a house warming of a family member. Started with cramps and then slowly pains in the shin and foot areas. Unable to stand or walk after getting up in the morning after painful night in spite of Pregabalin . All possible tests came negative after seeing all possible specialists. Now I am seeing a podiatrist who ordered tests called ABI and TBI to test blood pressure in the ankle and in all the toes. Waiting for results. I totally understand your pain and frustration….