Cause and effect?

I have had an essential tremor since about age 9, possibly earlier, to the best of my recollection. I have also suffered migraines since around that same time. At, or around, age 7 I suffered a head trauma when my cousin dared me to jump from the top of one bunk bed to the bottom of the other. When making the dive I hit the top of my head square onto the metal bar on the bottom of the top bunk which left me in a lot of pain. I suspect this may have led to these two problems.

Later in life i developed a bad case of Degenerative Disc Disease, which is affecting my spine from the lumbar through the cervical discs. This was compounded by several back injuries resulting in ruptured discs in the lumbar region, and bulging discs in the cervical region. I have also torn the rotator cuff in both shoulders, and had a minor unrepaired umbilical hernia for several years.

In January 2009 I had a lumbar fusion. In March of 2009 I started experiencing widespread pain throughout the body. Initially, I was treating these pains with topical creams and heating pads. These pains continued to increase slowly over time. Around this time I was also diagnosed with Sleep Apnea. I also had nights where the legs felt "odd" and would only feel well if I got up and walked around (this of course was later diagnosed as restless leg syndrome). I also developed Irritable Bowel Syndrome.

In December 2010 I could no longer delay the repair of the hernia and had that corrected. After this operation I found a large increase of the pain level troughout the body. The home treatments were no longer working welll enough. I also found pain through out the shoulder, arms, and hands when typing or performing any other fine motor skills. This pain would start after about 2 minutes of typing and continually worsen until it become unbearable after about 10 minutes. The arms and hands would also become numb with continued use. This is typically accompanied with increased stiffness and pain in the neck and shoulders.

In May 2011 I was diagnosed with Fibromyalgia.

Given the sequence of events provided, would I be correct in assuming that the back surgery resulted in the Fibromyalgia, which then resulted in the RLS, IBS, and Sleep Apnea?

Is the any link between a Benign Essental Tremor and Fibromyalgia?