Have you considered seeing someone who specializes in autonomic disorders? I am a white female in my late 20s and this sounds similar to me. That is the direction I am headed in. I also had mono more than once. My major issues are dizziness, excessive sputum production causing me to choke, spitting up stones, abdominal pain, shortness of breath, and I was diagnosed with neurocardiogenic syncope in the past. I recently saw a neurologist who thought I might have POTS but couldn't say so definitively because my tilt test results were borderline and the test performed while I was on propranolol. I also share these symptoms of yours: – joint pain
– joint stiffness
– brain fog
– trouble concentrating
– extreme fatigue
– dizziness
– pain in my left side, about where my spleen is, but doctors say my spleen is not enlarged
– pain in my ribs sometimes when I breath that lasts a few hours
-numbness and tingling in my hands and feet at times and especially when lying down.
i have mild dermatographia too but I was told that was nothing more than annoying. As a child the hives things happened to me too if i sweat. I currently get night sweats too.

Hope your situation improves!