I’m from Spain.
I write you because I’ve been noticing for two year than I have like tingling in my back and in my extremities when I’m concentrated in my respiration.
Before I use to notice when I was meditating.
I feel like energy in my body but after that my body is like before.
I need to have and explanation that what it is and how to improve.
I think the tingling sensation may be because you are not breathing correctly. First, your breath should be primarily in the abdomen area and very relaxed. Breathing naturally gets slower as we go deeper into meditation. You can check your breath by placing one hand on your upper chest and one hand on your abdomen. The upper chest should be moving very little and the abdomen should have the most movement.
If it seems reversed for you, try this: lie down, relax, and put your hands in place to notice where the breath (movement) is. It should be primarily in the abdomen. Then you can gently sit up and keep the abdominal breath going. This breath should be entirely through the nose rather than the mouth.
To watch the breath, bring your attention to the flow of breath where you feel it most clearly in the nose and place your concentration there. Do not control the breath but let it flow naturally. If your mind wanders, just bring it back to the flow of breath. You can mentally repeat a mantra as you watch the breath. On the inhale mentally say ‘I am’ or in Sanskrit ‘Hong‘ and on the exhale say ‘Spirit’ or in Sanskrit ‘Sau‘.
This is a very brief introduction to the Hong Sau meditation technique, a simple and powerful practice, which you can learn for free here. I recommend you go to this site to get more explanation of the technique and a demonstration.