Having Extreme Stiffness In Legs And Arms. On Healthy Diet. Suggest The Treatment?

Hello Sir, all of a sudden I have this extreme stiffness in my legs and arms. I can walk OK, but I cannot run at all. I am very healthy person, dont smoke, drink, or do any drugs and I eat healthy with good BMI and blood pressure. One morning I woke up and I became like this for reasons I cannot explain. Obviously I am not a doctor, so I cannot figure this, its an perplexing issue to say the least. How can you help? I did visit a Doctor, all he told me was that your fine and we take a blood test next week if your not well. Is there any pills or anything I can look in to? Thank you,