My hips feel very tight. Should I stretch harder?
Usually, no. “Tight hips” can describe many different sensations, and the structure of the hip joint differs from person to person. Forcing a deeper stretch assumes that every limitation is simply a short muscle waiting to be lengthened, which is not true.
Yoga gives us a more intelligent approach. Explore several directions of hip movement, use props, develop strength around the joint and observe whether the sensation changes as the body warms. A useful stretch should feel workable and should leave you able to breathe normally; sharp pain, pinching or catching is a reason to change the position.
The tradition teaches ahimsa — non-harming. Applied to asana, that means progress does not come from declaring war on the body.