Is chronic low back pain and pain in right leg due to unilaateral sacralisation (right) and what are the options?

Dear doctor,

I have been suffering from pain in right leg and low back since last one and a half year. I am a military pilot having been involved in extensive flying activities for last 19 years. My age is 40 yrs. The problem of pain in right leg and low back has considerably increased in last one year. MRI findings in Jan/Mar 08 are:

i) DDD L4-L5, diffused bulge L4-5.
ii) Unilateral Partial sacralization LV5 (Rt)

Jan 08 (xray) Lumbar Spondylosis, unilatreal sacralization (Rt).
Sep 08 ( MRI) disc bulge L3-4, L4-5, Unilateral partial sacralization Lv 5-S1(Rt)

The X-ray findings of 1986: spinabifida occulta and sacralization of LV5 right.

There have been few episodes of unbearable low back pain (spasm) in the spinal region radiating down. The low threshold pain in the rt leg is always present(particularly in thigh). This worsens progressively as the day progresses, especially after prolonged sitting/exertion. During the reflex check on my right leg, it is very apparent to me that the reflexes in the rt leg are way below the left leg.But the doctor says that as per MRI he doesnt find any nerve damage.

During walks there is a progressive increase in pain/discomfort in the right leg especially down to heel. I am being treated with Gabapentin and Amitryptlin ( plenty of side effects including lethargy, heaviness etc) since last 8-9months.

Therefore, I would be grateful if you can kindly advise me on my case and specifically on the the following:

* Are my current problems attributed to the MRI findings?
* Are nerves in the sacralized area compressed, although not visible in the MRI, and creating pain?
* Have my current problems been aggravated by my profession as a pilot in the aircraft involving vibrations/stress and hectic non-stop schedules?
* What are the chances for improvement in my symptoms if I continue the flying duties as a military pilot?
* Since the symptoms of pain alongwith the side effects of prolonged medication ( Gabapentine and Amitryptilon )   have been so much aggravated that I cannot do even routine office job, what are the options available with me vis-a-vis profession and health?

Regards