Meditation causing headaches

In the last couple of months, I have experienced a chronic headache in my forehead. After checking with doctors etc, nothing could be found. I then kind of had the intuition it could be related to my meditation practice. For more than the past 2 years, I meditated daily for 20-30 minutes or more. I have read some articles online that say that focusing on the breath (especially in the nostrils, which I used to do) could lead to an accumulation of energy around the third eye chakra, and it seemed to me my pain felt exactly like this. I have now taken a break from my daily practice and the headache got much better and nearly disappeared. \ But as I stopped meditating, I really miss the peaceful state of mind and presence I had before, so I would like to start again soon. I would be so grateful to get tips from you on this.