So I need some advice, I've been cycling for a few months and I'm in great shape and I've been doing longer routs without a problem. Recently I've been doing 40 mile rides and as soon as I hit about 30 miles, I get a muscle spasm on my left shoulder blade area and my lower back starts hurting. Nothing else hurts and if it wasn't for that, I could go further. I don't feel like I'm putting a lot of pressure on my hands because they never hurt, so I'm not sure if it's the distance of my bars, or if my seat is not tilted the right way. Since I'm fairly new to this is can use some advice