Singulair and ulcer

My daughter had extreme nausea when she was on singulair, along with joint and body aches. She is no longer on singulair ,just advair and zantac and her peak flows have more than doubled. My daughter also at age 10 suffered for 3 months with stomach aches and eventually headaches. She missed over 80 days of school in the 5th grade. We had every test in the world ran, she intially was diagnosed with an ulcer and was put on ulcer medicine but kept on getting worse. After 6 months of this we finally gave up and took her to the Mayo clinic. She never had an ulcer, she had abdominal migranes, symptons include severe stomach pain, nausea and lethargy. She never really got any headaches until her teen years. She was put on a migrane medicine and was back to school in 3 days. She seem to always get the pains when she was overly tired or stressed out. She was on migrane medicine for a year and then taken off. She now manages with over the counter meds and tries to get more sleep. Apparently abdominal migranes are quite uncommon, but they do manifest in younger children and the main complaint is usually stomach isuues. Hope this helps.

My son is now 8 & has been on Singulair for over a year. The past couple of months have been a nightmare with trips back/forth to the dr for major stomach/belly pain. He's missed some school due to this. Still after all the tests (blood/belly & the barium swallow) he's still having pain & we can't seem to find any reason. Could his problem be related to Singulair? Any info (or website) that goes deeper on the side effects would be greatly appreciated! I (his mom) is in the process of getting an ulcer due to worry over her child!