This post is an attempt to capture some of what I have read about weird experiences during one’s spiritual quest. It can be a very odd and unnerving experience to run into these things and it helps to know others have run into it too. Some of these to this day are hard to believe for me.
It is also important to get proper medical guidance, just incase it is really a health issue. As an example, it is quite possible that the weird energy or heat is jusy dry skin as in my case needing some moisturing lotion. It had never happened to me before, so it was hard to believe! 
The reasons for this vary from Indian Yoga\Tantra scriptures (Hatha Yoga Pradipika, etc) mentioning it as kundalini or prana awakenings, Stephen Cope mentions it as stuck emotions and feelings, others call it part of raising your vibrations.
1. Stephen Cope’s book: Yoga and Quest for the True self (chapter 15: Meditation in motion)
1.1 Severe Neck Immobility
Neck went into a death grip spasm and he could not move his head for amonth. He saw every conceivable form of health practitioner to no avail. Finally, it just disappeard
1.2 Severe sweating during night
He went almost an year of sweating profusely at night, soaking up his clothes.
1.3 Scalp broke into a nasty eruption of pimples.
1.4 His right leg would kick violently and shake during deep states of relaxation.
Suggestion: Stay with the experience and develop awareness about it without judgement (disliking or liking it). If the experience is too much to bear, reduce the practice for a short while.
2. Dipa Ma’s experience during a meditation retreat.
From the book, Dipa Ma: The Life and Legacy of a Buddhist Master by Amy Schmidt,
She felt has if somebody was gripping her leg and she could not budge from her standing location for 30 minutes.
3. Sylvia boorstein, Buddhist teacher and author,
from her book, That’s Funny, You Don’t Look Buddhist: On Being a Faithful Jew and a Passionate Buddhist
During a retreat, she woke to energy experiences through out her body which she described as unpleasant and disturbing. Her limbs would vibrate or spasm in random movements in public places. Her body temperature stayed normal, but she felt severe cold or thought she was radiating heat.
4. Buddhist teacher, Jack kornfield
His head started shaking back and forth for hours at end. Then, this arms started involuntarily flapping like a bird’s wings.
There is another category of experiences for those doing astral travel (Erin Pavlina is a good reading source), dream analysis (Conscious Dreaming: A Spiritual Path for Everyday Life by Robert Moss is a good reference)
Another resource, though not actively updated:
Jamie documented his spiritual experiences with yoga and pranayama in his blog.
