I'm not feeling (very) well.
我觉得不大舒服。
How are you feeling,exactly?
您感觉怎么样呢?
What seems to be the trouble?
您感觉像是什么问题呢?
Is there anything I can do?
有什么我能帮忙的吗?
I have a cough and a runny nose.
我咳嗽,又流鼻涕。
Do you have any medicine I can take?
你们有没有我可以吃的药?
I don't travel very well.
我旅行时一向不大舒服。