Ruptured tendon in calf week ago-dr gave me stretching exercises but leg hurts after all day- shud i take pain killers to stretch more so heals better?

Degree of rupture? : Yes, but this does depend on the degree of rupture. The most common rupture near the calf is the achilles tendon, and if you had a full rupture, or even a significant rupture, stretching may not be the best things as it will cause less approximation of the tendon to heal. I have not seen your imaging or know how much function you have in it, but you may need a second opinion.