Dear-Thanks for using our service, I understand your concern due to multiples pains. Your muscle pain in the calf and forearm could be secondary to electrolytes imbalances as sodium,potassium,calcium and magnesium.Sometimes we dont eat adequate and can have low levels of these which are very important in muscle contraction and can give you pain.Other possibility is dehydration, it is important to drink at least 32 onz of fluid to replace our basic needs in the body. The headache and left side pain from the kidneys can be related to low water intake. The knee pain can be low calcium or just arthralgia due to heavy exercise. I recommend you to drink water,replace the basic electrolytes and if no improvement,see your primary care doctor for a laboratory exam and checkup/ I hope that my advise has been helpful Dr.JC