My right side of neck has been hurting all day and feels stiff cause ? carry a heavy backpack everyday to school

Blame UR back pack: Make sure you aren't carrying more than 10 pounds of books and supplies in your back pack or you're becoming a pack mule, and creating a neck and shoulder strain on yourself. This is not good in the long run! Also, you have high blood pressure, so any additional workload to your heart, walking with a heavy backpack for long distances isn't wise either. Talk to your doctor about this.