both Pulmicort and Azmacort list back pain as a significant side-effect (this means statistically significant -- only about 5% of those recieving treatment had it), it's small, but it is listed.
Headache is a much more common side-effect. Singulair lists dental pain as a side-effect.
Neck and shoulder aches (most commonly neck aches) can also be a symptom of TMJ dysfunction. Many asthmatics find themselves with TMJ dysfunction from the disturbed sleep and stress that having this condition while uncontrolled can cause. Talk to your doctor, or a chiropractor about these pains you feel. They may be unrelated to your drugs -- and if they are related to your drugs, chiropractic adjustments can be made to help you breathe a little easier so that you may be able to reduce the dosage of your meds.
You could also try switching to another inhaled steroid, as they all seem to have slightly varying degrees of back pains. Flovent still lists back problems as a side-effect, but in doses less than 500mcg twice daily, they occurred in less than 1% of the subjects tested.