What Causes Episodes Of Dizziness And Stiffness In The Neck?

Question : Yes please... thank you. about 1 1/2 years ago I started having episodes where my heart felt like it got slapped hard and that feeling went away but instantly a strong dizziness overcame my whole body and then felt like I was going to have a stroke. If were standing I'd start shaking and sweating. It only lasted 15 - 20 minutes each episode and it was weeks apart. This year as of about 2 months ago it has occurred every day and the dizzy symptoms sometimes last for hours. I can not walk more than 15 minutes consecutively without having an episode. I've been to the ER 4 times for this. The neurologist ruled out issues on his end. The cardiologist recently started me on a beta blocker to slow my heart rate down but it's not helping my symptoms. He did an ultra sound and found turbulence in the left neck artery but wanted a ct scan of neck and head and waiting on those results. he said he doesn't think the artery is an issue and certainly it isn't causing my symptoms. I had a stiff neck for 4 1/2 months until XXXXXXX and changed my diet cutting out coffee and the neck pain went away. I can not have caffeine or drink alcohol or instantly it causes the dizzy episodes which then turn into feeling like I'll have a stroke. The ENT did an ENG and it's normal yet said he sees something abnormal in the neck. Bloodwork has been taken to see if I'm diabetic, thyroid issues, anemic and/or other issues and it all checks out ok. I'm not having panic attacks, I love my life other than this debilitating issue that is keeping me from doing normal activities. Thanks.