Riding a bike can be a lot on your upper body if your posture isn't right. Here's a helpful video on how to get your spine right while riding your bike that helps your body work for you.
The 3:00 slump is something that affects almost all of us. You've been at your desk for a while, that piece of chocolate in your drawer you ate as a treat felt like a boost but now your sleepy. Your shoulders and upper back hurt and your head is forward.
Sound like you?