Singulair I am a 28 year old male. I was just pre-scribed Singulair yesterday to help with my acute spring alergies. I took the pill at 9pm. I am now up at 4am on a work night writing this. I am freaking out and almost went to the hospital until I read this site and already feelling better knowing that this medication is horrible for some and some of these side effects are expected. My throat and chest are really tight/sore (the worst possible feeling). I have a cough that is awful and hurts. I also have the chills and feel like I am running a fever. I cant sleep. I hate this medication....never again.