I practice Ken Cohen's stuff too, his One Finger Zen Meditation has a more powerful effect on me than any of the exercises in Level 2, it goes quite well with Yijin Jing.
It seems that you may have some hidden blockages and Qigong practice makes your body aware of those blockages. Keep going with your practice. If SFQ doesn't work, go for another style of Qigong, don't give up.
Also, you may want to get a free healing from Michael Mohoric, He does a free distant healing every first week of the month. It feels like practicing Qigong for a week non-stop if you're under his Qi, here's his facebook page:
https://www.facebook.com/Qigong.Distant.Energy.Healing?ref=ts&fref=ts
