If I meditate standing my breathing is good, in and out naturally flows. When I sit cross legged it is like my breath feels restricted, does not flow the same and I feel I need a help it to work and it feels a bit shallow, especially on the out breath. Helping it gives me tension. My posture feels okay, I sit legs folded in, on a cushion, pelvis tilted okay and back seems quite straight. Are there exercises or stretches which maybe will help me?