A rheumatologist diagnosed me with fibromyalgia, and the pain is just like what you describe, as well as an overall general pain, certain parts of the body feel like they are bruised, though there are no visible bruises there.
You could do a self check to see if any other areas such as hips, knees, shoulders, backs of arms etc are sore to the touch. I was surprised to find out how many parts of my body felt bruised when the Rheumy did my exam. My hips were so painful I literally screamed and nearly jumped off the table when he checked them.
Keep in mind I'm a relatively young person, so it's not an age related issue. Myalgias are listed as a symptom of Lyme. I'm not an expert, though, but there's plenty of literature on Lyme and myalgias including fibromyalgia.