Dear Trinity,
I am not sure why you are having these shocks when you meditate, but one possibility is that your body is not relaxed. I suggest you experiment with strategies to relax the body and see if it helps.
Proper posture is essential for a relaxed body during meditation practice. When we sit to meditate we need to preserve natural curves of the spine at the lumbar, thoracic and cervical areas. It causes tension and pain to sit with a ‘military straight spine’ with the curves flattened. You should be seated upright with knees a bit below the hips on a chair or meditation cushion. Feel free to add a cushion or folded blanket under your hips to increase the tilt of the hips. If we have a posture where knees are at hip level or above the hips, the spine will usually round forward, causing tension in the back and neck. If in a chair, your feet should be flat in the floor. Sometimes when seated in a chair a cushion behind the back is needed if your spinal postural muscles need support. If not it is best to sit with back away from the chair.
Once you have a proper seat, turn the palms upward, resting on the thighs, and draw them back toward the junction of thigh and abdomen — but not so far back that your wrists feel cramped. This helps open the heart area and bring the head into balance on the spine. Feel like you are lifting the chest-heart area upward and drawing the shoulder blades together. Then glide the head back so it is centered on the spine with the chin parallel to the floor. If the head is too far forward relative to the spine, or if the chin is tilted upward, it will cause tension in the neck.
Your position should allow you to sit comfortably for 10-15 minutes or longer without pain or body parts ‘going to sleep’. It can help to have someone check your meditation posture from the side. Here is a video that is helpful: How to Sit Properly for Meditation
Another helpful tool for relaxation of the body and preparation for meditation is yoga postures. Try doing 10-20 minutes or more of postures prior to sitting for meditation and see if decreases the ‘shocks’. Ananda Yoga is particularly designed to prepare the body for meditation. This YouTube video, Ananda Yoga for Meditation, takes you through a hatha yoga practice specifically designed to prepare for meditation. I encourage you to try this and see if it helps you have a deep and still meditation.
These two strategies should help a lot. If you are still having the shocks after trying these it might help to have a meditation technique that is specifically designed to take you into deep calmness and centeredness. The seating video I directed you to earlier is part of a free mini course in meditation which will teach you a simple and very effective meditation technique. You can view the entire course here: Meditation Mini-Course.
Many blessings,
Nayaswami Mukti