What would be a harmful side effect of cold medicine?
a. you have chills throughout the night
b. your nagging cough goes away
c. your runny nose has dried up
d. you break out in itchy hives

A harmful side effect would be breaking out in hives. Yes, having chills is detrimental to your sleep, but not dangerous. Hives are a sign of anaphylactic shock, something that can kill. If you break out in hives from a medication, you should call an Urgent Care. If you get hives and labored breathing you should call an emergency room. 

The best way is to swollow and hold in your breath

Nothing will delay it, but drinking some lemon (squeeze 3) would cut it, making it last a few days, but its not good to do that. won't hurt you but the next month will be more cramps.. take some advils with you on the trip