The pigeon pose, basically, stretches your thighs and shoulder and it is considered as the best exercise for those who suffer back ache. The asana also eases chronic lower back pain. Here are the steps-
Steps:
1.      Stand straight on the yoga mat, and come into the dog pose while inhaling.
2.      First bring the right knee on the floor near the right wrist and lower down the left leg to the floor and stretch it towards the back.  
3.      While keeping the left leg straight, bring the right foot close to the left wrist.
4.      Hold the pose for 5-10 counts or as long as it is comfortable.
5.      Repeat the same cycle with left leg.