Add Yahoo as a preferred source to see more of our stories on Google. Those stiff, painful spots can take up to two weeks to go away on their own. Sophie Walster/iStock via Getty Images Plus Imagine ...

If you’ve got a lump on top of your shoulder muscle, you have a good chance of it being a trapezius knot. This type of lump in the trapezius muscle — called a myofascial trigger point — is among the ...