Can I meditate while lying down? also a question about opening chakr

[THEB!GBOWSSS]

I have two metal bars in my back from reconstructive spine surgery, so when I sit in the lotus position to do my meditation work I get terrible aches. Is it possible to lie in a corpse position for chakra work, void meditation, etc.?

also, whenever I do the power meditation routine for opening chakras, I find the routines very brief, like 2 minutes, is this okay? or am I doing it wrong? If i'm doing it right, then i'll continue doing these power meditations in the lotus position while doing regular meditation lying down.