I have been meditating for the past 15 years. Over the last year I have noticed a vacuum pressure feeling in my ears and skull, the feeling is rising me upward. Sometimes I get energy spasms for a few seconds somewhere along the spine. Also, now I notice that for a few moments the right half of my body either goes numb or full of energy. Why?
You don’t mention what form of meditation techniques you are practicing; that information might help me to answer your question a little more clearly.
But in any case, the physical sensations you are experiencing are not unusual. At some point in almost everyone’s meditation "career," physical sensations will occur during meditation, such as pressure in the head, numbness, energy spasms, eyes watering, over-salivation, and so on.
Most likely, it is nothing to be concerned about. Pray for help and guidance for God and/or Guru(s). Relax more, particularly relax in any body part being specifically affected. It will go away eventually.
Why is this happening? Meditation is a purification process. Energy begins to move in your subtle body as the "old baggage" or various forms of stored stress begin to break loose in your energy spine; this process causes things like you are mentioning to happen. It is a good sign — a sign of spiritual progress!
So pray, trust, be grateful, and continue onward on your spiritual journey.