My head hurts as soon as I enter the hotel, and I have nightmares?

Let's rule out psychological factors first. It may be because some rooms have ceilings, or the rooms are relatively low (sometimes I don't realize it, but there is a height difference), which will make people feel depressed and their hearts beat faster, and some will feel headache and lack of oxygen. Coupled with the unfamiliar environment itself, some people will have a sense of obstacles.

The quilt and pillow are too thick (compared with their usual) and feel uncomfortable, which will lead to a decline in sleep quality. Another possibility is the orientation of the bed. Some people can't sleep, and if the direction of the bed changes, they can't go into deep sleep. (but this possibility is relatively small after all, so I won't say it here. If you have any questions, you can Baidu it. )

There are also psychological factors. If it is a psychological problem that affects life, it is recommended to have a look.