Will Bus Journey With Pain-killer Worsen The Neck Sprain?

on 17 apr my neck muscle and left upper part of body get stiff. Even a small movement in body or jerk was giving me tremendous pain in my neck muscle and shoulder.Latter doctors told me it neck strain. I took painkiller injection to overcome because i have to board bus for 12 hr journey( it was urgent).But i didnt get relief and i finaly missed my bus and board flight after 3 days. i just want to no is it possible to go for bus journey in such condition with the help of pain killer.