Singulair and pelvic bone

I have major bad effects from strong perfumes, more of a chemical intolerance/autoimmune response (body aches, fatigue, irritability, difficulty concentrating) than nasal or sinus type reaction. This gets worse as the years go by. One of my former coworkers drowned herself in strong perfumes every day. I felt like I had the flu all the time and my other co-workers could barely smell the perfume. My doctor put me on Singulair. It was like a miracle, I was almost unaware of the perfume and my symptoms were gone. I left that job at the end of Feb. 07 and stopped the Singulair immediately. Within 4 or 5 days, I was completely crippled by lower back pain, right at the top of the pelvic bone, started in one side then moved to the other. Spent most of a week not being able to move, walk, etc. I started another job mid-May and started the Singulair again due to the entire place being landscaped with jasmine, another of my major triggers. I left that job after 4 weeks, stopping the Singulair immediately again. Now, several days later, the back problems are returning and worsening. I've never had lower back problems in my life. I am thinking that the crippling back pain may be due to the sudden cessation of Singulair. Any thoughts on that, anyone? I also wish I had read these comments earlier, because during my last 3+ weeks on Singulair, I was waking up after a couple hours of sleep and unable to go back to sleep due to mind racing, was uncharacteristically unable to cope with stress, etc. It was a nightmare that I blamed on the new job and now am wondering if it was not caused by Singulair.