I’m practicing meditation since 4 months and since a week I started feeling throbbing somewhere around the end of spine. It’s too intense sometimes that I can feel jerks in my body. I searched for it but found medical conditions only. Is it some medical condition or something else? Also I feel itching on different spots on my spine like around back of neck and chest.
What you are feeling sounds like an awakening of the kundalini energy in your astral spine. This not a bad thing to have happening; it is a good sign and necessary for spiritual progress to take place.
However, people new to meditation often need some advice about how to your meditation practices, especially if it feels to you, as you have said, that you are experiencing [painful?] throbbing or too much intensity of various kinds.
First of all, it would be helpful for us to know what sort of meditation techniques you have been practicing for four months. Are you preparing for Kriya Yoga Initiation through Ananda and practicing our suggested meditation techniques? Could you let us know that, so that we may better advise you?
If you are doing breathing exercises, which are too intense or go on too long, or other such excessive practices, this might explain your discomfort. As for the itching, that sounds more like some sort of a medical condition, which would be good to have checked by a physician.
I see you live in India, so it would be an excellent idea for you also to discuss your meditation practices in person if possible, with one of our Ananda teachers there. See anandaindia.org.