My device gets warm is that normal?

Yes when a protocol is running the vibe should get warm up to 105°F which is perfectly normal. 105 Fahrenheit is what reasonably hot water would feel like on the inside of your wrist.

https://resona.health/2023/04/27/my-vibe-gets-warm-is-that-normal/

The device is supposed to get warm, up to 105F,  that means its working. For the best experience, the VIBE should have "some" ventilation especially if one is temperature sensitive. You want it as close to the body as possible, but it does not need to be against the skin to be effective. The Express and Awake protocols are some of the highest frequencies on the VIBE and may run the warmest, so make sure you have adequate ventilation for those protocols or any that feel too warm for you.

Bottom line - If you think it to hot for you, it needs more ventilation and/or turn the power level down slightly.