When the energies of kundalini first arise many people do not recognize them as an accompaniment to the process of spiritual realization. These energies curling up the spine or raising heat and jerks and strange body movements sometimes occur during meditation, or following yoga or Qigong or breathwork, and even happen spontaneously without any discernable trigger activity. Even in those who are doing practices that encourage spiritual awakening they are often not recognized for what they are -- the subtle energy field clearing away stress and old patterns and opening channels for the awakening of consciousness.
Our bodies are our vehicles for consciousness and awareness to experience itself in the flow and experiences of the human condition. The life force caught hold as we were conceived and moves through us throughout our lives. This force is both energy and consciousness and when we awaken spiritually it intensifies and expands and shifts our perception and experience of what we are and how creation appears. This shift is called awakening in non-dual circles.
It can take months and years for a kundalini process to mature, as the energy may wind slowly through the body, rise and fall intermittently, and flush out emotional, physical and psychic issues that have been dormant or repressed. So it is disruptive and frightening for some people. The fear is often because of the strangeness and the unfamiliarity of the random movements and experiences.
Fear creates contraction and this promotes more releasing of stress, so the sense of difficulty can be increased. I suggest if this is happening to you that you substitute the energy of curiosity for fear, and relax into what is happening, as this can help the releasing in the moment to pass through more quickly. Fear is just a thought followed by energy. It will not serve you in this process.
Although for some people kundalini awakening is primarily gentle or energetically blissful, it can be challenging for others to accept and live with the challenges of this process, and nearly impossible to make it stop once the energy has opened as far as the throat chakra. Before then stopping all energy and spiritual practices, eating root vegetables and protein, or doing grounding practices like gardening may help the energies calm down a bit. There can be brief energy releases that are known as prana-tattva (in yogic science) that happen only once or rarely -- this is a release of a blockage or stress held in the body and are not the same as kundalini arising. If the energy stops completely it was originally not a full activation but just the preliminary pranic releases.
If you are in the throes of this experience you may find my books The Kundalini Guide or The Awakening Guide helpful as they were written for those who need to understand the changes that support spiritual awakening and offer methods that help it happen with less confusion and discomfort. Yes, awakening brings bliss and insight and an internal sense of being love -- but for this to happen everything that is not so peaceful needs to be released. If you have longed to know Truth or what is God or what this human existence is about and followed spiritual practices to get there, you need to learn to accept with equanimity the process of transformation.