I've found using an at-home massage pillow (with heat) helped me get over my two year PCS. (Back story- 37 year old male hit with trunk tailgate. Symptoms: headaches, dizziness, visual issues.) Headaches and neck pain lingered for nearly two years. Tried a lot of things with minimal effect. Went to chiro and had neck pillow massage and noticed slight improvement- so I bought one myself and worked on my neck/head a couple times a day at first. Gradually the symptoms subsided, until one day I woke up and realized everything was back to normal.

For what it's worth. Maybe this info will help someone else.

Good luck!