I am a 21 year old male, 255 pounds, 6 2. For the past 3 days I have been sick with no fever. I did drink pretty heavy 3 days ago but do not know if that has anything to do with it because my girlfriend starting feeling a bit sick today too. I am usually hot and have the Air Conditioner on but the last 3 days I have been cold when it is hot, the chills right? The first day I had bad diarhea, the second and today it is constipation . I have a pain that radiates from my left back where my shoulder and top left lung is and it radiates down to the bottom of my rib cage. I am a little constipated, but am eating easy to digest, low fat , high fiber foods with four cups of tea a day and lots of water. The pain is constant and irritated. I would describe it as dull. I tried to ice different areas of my back to see if I was just really stiff because my posture is horribly bad because I only JUST started exercising recently and am in front of the computer a lot. Feel a bad stiffness in my neck that crackles and makes snapping sounds if I have it in the same position for just a minute then move it, that would be bad posture too correct?