A TSH level of 19.75 indicates hypothyroidism (an underactive thyroid), which commonly causes muscle aches, joint stiffness, and fluid retention, leading to foot and back pain. Fortunately, this is a very common and highly manageable condition. The standard treatment is a daily prescription generic medication called levothyroxine to restore your hormone levels, which should gradually relieve your pain. For temporary relief, mild over-the-counter pain relievers like acetaminophen or ibuprofen can help. Please consult your physician for a simple blood test confirmation and to receive the correct prescription dosage. You will likely feel much better once your treatment begins.