What Causes Headaches And Pain In The Body?

Hi, I'm unsure how to go about this because I have so much going on with my body at the moment. I have headaches all the time to start with. I also get pain on the left side of my body but it's not like I'm having a heart attack. I'm 24 and I'm in relatively good health from what my own doctor has told me. They are sharp pains in my chest and my legs seem to get affected by it , too. I get random sharp pain in my shin and weakness everytime I want to start to walk around after sitting for a period of time. Weakness in my feet to be exact. I'm not sure what this all means and if I should see medical attention.