One study has found decreased tear production in 90 percent of those with fibromyalgia.

Experience has shown that dry mouth is also common, aggravating dental and digestive problems.

In those who suddenly get a bunch of dental cavities along with their chronic fatigue/ fibromyalgia (CFS/FMS), dry mouth is the usual cause. This occurs because saliva is critical for preventing dental infections.

Dry eyes and dry mouth are treatable. They are caused by autoimmune disorders that injure the glands that make tears and saliva, but also is aggravated by nutritional deficiencies and many medications.

Some doctors who are not familiar with CFS/FMS immediately think of an autoimmune disease called Sjogren’s syndrome — and go chasing the wrong problem.

Though Sjogren’s syndrome can cause CFS/FMS, it is less common, and a Sjogren’s diagnosis should be confirmed with an SS-A and SS-B blood test and a simple biopsy.

If you have widespread achiness and fatigue with insomnia, think fibromyalgia.