[BAD Boys]

I never played drums in my life but it's my favourite instrument and I have little idea about how it's played. 3 weeks back I bought myself an electronic drum kit, since I didn't have a throne I sat on a chair and starting hitting pads, bass, hi hat. After couple of hours I managed play a simple rock beat, I couldn't believe myself. The issue is, the very next day I started getting little pain in my lower back, after few days it became worse. I went thru net and found out that maintaining inproper posture leads to sever back and spine injuries. I didn't want to give up, I bought a throne and continued playing with proper sitting posture but now I have the lower back pain whole day, it's terrible. Can someone help me PLEASE?