Jabbing Feeling During Meditation

I had finally begun to meditate on a regular basis for the sake of enhancing my abilities and attempting to astral project. One day, as I started to feel some of my chakras opening, I focused on my where my heart chakra would be. As soon as I had though, for some reason I felt this jabbing pain, like someone was taking their index and middle fingers and pressing it quickly and roughly square into the place on your chest just between the part where your ribs seem to open up sort of like chest compressions, only not (if you know what I mean).

I tried to stop it so I could get back to my normal meditation by not focusing on it anymore, (I didn't want to waste almost an hour of meditation feeling like someone was striking my chest) but the stabbing continued so I just decided to stop for the time being.

I soon attempted meditation again that same day as I felt that maybe I could find out why what happened earlier happened, to see if I could get through whatever that pain was, and if it were only for the one meditation, but it started up again and I didn't have my questions answered. By that point I just got frustrated and decided to call it a day.

I found that it doesn't always happen every time I meditate though. It only happens sometimes, and only in that one area. I have considered it possibly BECAUSE I tried to open it that it started hurting. However, I have opened my heart chakra before, so that is out. Could it be some kind of weird block? And, if so, how do I make sure it's fixed completely? Any help and advice would be greatly appreciated. Thank you all for reading my story.