There are numerous different metabolic conditions that cause symptoms of muscle fatigue or muscle burning with exercise. Some of these conditions relate to the way the muscles process a particular type of energy called glycogen. Others are a dysfunction in the way a subcomponent of the muscles cells, the mitochondria, processes energy. Evaluation for any of these conditions requires a visit to a metabolic specialist for a comprehensive examination and, if there is any suspicion for one of these conditions, specialized laboratory testing which can include both blood and genetic tests and also, sometimes, a muscle biopsy
At the same time, however, it is important to emphasize that these metabolic conditions are all extremely rare. There are many other much more common causes of muscle pain
or muscle soreness including certain prescription medications, problems with the thyroid gland and - most commonly - simple physical deconditioning. Therefore, before considering a metabolic problem it is always important first to have these simple and more common things ruled out, which you can usually do in collaboration with your primary care doctor
If you haven't talked to your primary care doctor about your symptoms I would start there, and only then consider a metabolic doctor.