I have been taking Singulair for about two weeks now (I am almost...

I have been taking Singulair for about two weeks now (I am almost 50) and since I started taking it have experienced terrible pains in my bones of my legs, to the point that I can almost not walk. It is especially prevalent at night, which is when I take it (I was told to do that as it would make you "sleepy" - I haven't found that). Has anyone else experienced this type of pain when taking it? I can't tell if it is just a coincidence that this started for the first time at the same time and has progressed badly as I take it, or if it is really related to the Singulair. I would appreciate anyone elses comments on it. Thanks.