Why Is MDMA Causing Tightness In My Body?

Hi. I am a 23-year-old female, very healthy (runner training for a half marathon and eat a mostly organic, vegetarian diet including lots of organic produce). I took 3 pills of MDMA earlier today (over the course of 6 hours), but noticed some tightness in my left bicep and the muscle behind my left shoulder after taking the first pill. I didn t end up getting a high from taking the pills, which leads me to believe that they were not pure MDMA (but the absence of a high seemingly excludes the possiblitiy of a presence of other drugs). This was the first time I have ever taken Ecstasy or pure MDMA . I m now having chest tightness and a rapid heartbeat (regular, just very fast). and the most concerning part to me, is my left wrist feels tight, almost like its being squeezed by a blood pressure monitor. And my left had is tingly and stiff. What could be going on?