Well, it is true that our attitude plays a very important role in coping up with the pain. People with positive attitude heals faster than people with a negative attitude and negative thoughts. So it is very important to stay calm & positive during your treatment and do not overstress yourself.
To reduce stress and to control anxiety you can do meditation on a daily basis. It is also helpful to promote emotional health.
For side effects, you can consult with your doctor he can suggest you some good options to cop up with them.
Btw good luck with your upcoming treatment!