Why do I wake up feeling sore and exhausted?

I am 19 years old, I work for Tim Hortons. I work about 4-5 days a week for about 5-8 hours a shift. I realize that this type of working environment can cause aching feet and muscles. Lately, even on my days off (I sometimes get 3 to 4 days off in a row) I will wake up to pain in every joint of my body. My neck, my fingers, my back, you name it. I also feel like the 8-9 hour sleep I had that night had no effect. I wake up wanting to fall back asleep and my eyes are stuffy. This happens to me every morning. Why am I feeling so out of it and tired after a good night sleep? And why does my body ache? I'm only 19 and I've been at Timmies for 1 month. I eat healthy, I eat more vegetables than the average person and I have a fixed diet. I don't smoke, I rarely drink. I do crack my knuckles quite a bit so that may be why my knuckles ache in the morning. I would really appreciate a reply to this question! Thank you.