Why do certain muscles spasm randomly when doing a simple task like just picking up a backpack that you’ve picked up before fine but after it feels really sore?

Question

I don’t know if it’s muscles I’m talking about or another part of the body – I can’t think of right now sorry. I went to pick up my work backpack the same as I do everyday, but yesterday and my shoulder more so like neck area completely spazed and it was a burn. I hate that feeling. Today my neck and shoulder are so sore why does the body do that? Is it the same as a Charlie horse??

In: Biology

Answer 1

Basically when performing easy tasks you are less focused on doing them and more apt to injure yourself by doing something incorrectly form wise. Many people end up with slipped disks and back muscle spasms just from bending over to pick something off the ground