If it's muscle related, you do take Magnesium, right? I take amino acid chelate magnesium (not Magnesium oxide which has low absorption) and my sore "arthritic" knees now work almost perfectly again. In the Bible, the Lord told us what foods to eat because they are high in the nutrition we need. But this day and age, they modify the foods so much that we sometimes need a bit of a supplement to help out.
On a side note here, the Bible has answers to all our physical health and nutritional needs - we can get both physical and spiritual healing. Whenever they come out and say such and such is bad for you, I go to the Bible and prove them either right or wrong. For example, I don't restrict my salt intake despite them saying salt is "bad" for you. It's only a problem if salt makes your body swell. But for most people it does not - but they give a "one shoe size fits all" advice in saying for EVERYONE that "salt is bad" because of what it does for a few. They are in severe error. You have to become educated, pray to the Lord for wisdom, and experiment yourself.