You symptoms are likely due to;
1) Autoimmune disease
2) Hormonal issue; adrenal function tests, parathyroid hormone assay are advised.
4) Chronic fatigue syndrome.
Some of the investigations which are necessary to be repeated are;
1) Thyroid-stimulating hormone
2) 25-Hydroxy vitamin D level: Low levels can cause muscle pain and tenderness
3) Vitamin B-12 level: Very low levels can cause pain.
4) Iron studies including iron, total iron binding capacity, percent saturation, and serum ferritin
5) Magnesium: Low levels can lead to muscle spasms, which are common in fibromyalgia; magnesium supplementation can also improve symptoms in some fibromyalgia.
6) The erythrocyte sedimentation rate (ESR)
7) Antinuclear antibody (ANA)
8) Rheumatoid factor.
9) Serum electrolyte level measurement
10) Immunoglobulin M (IgM)/immunoglobulin G (IgG) coxsackievirus B titer
11) IgM/IgG human herpesvirus 6 (HHV-6) titer
12) IgM/IgG C pneumoniae titer
13) Autoimmune panel
14) Anemia panel.
15) Antipolymer antibody assay; present in approximately 50% of patients with fibromyalgia. This biologic marker may provide conclusive evidence for a subgroup with fibromyalgia.
16) Sleep studies.
These are likely to reveal the line of management.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
Thanks for using Just Answer.