This is yet another example of a subtle disease that can cause chronic pain and easily go undiagnosed for years: AMPD1, adenosine monophosphate deaminase 1 deficiency. Genetic. Rare, but not crazy rare. We’ve all met probably someone with this. Often asymptomatic.
But when there are symptoms? Muscle pain, cramping, weakness, fatigue. Vague, non-specific symptoms. All symptoms of other things! Symptoms that often don’t even trigger suspicion. When people have symptoms like this, unless they are very bad, they often just think things like “aging sucks” and “I’m just weird that way … I guess.”
And even when people do take symptoms like this seriously, they know (or find out the hard way very quickly) that it’s very hard to get doctors to take them seriously.
I have added this one to my tour of the many, many possible causes of persistent pain: 35 Surprising Causes of Pain.