6 weeks post op of Breast Lift, are dissolvable stitches supposed to be tender and painful when they are dissolving?

Yes. Dissolvable stitches can spit, be tender, and cause pain even though the skin has healed. There are a number of reasons for this including the actual type of suture used (braided suture is more prone to spit than monofilament), cleanliness of the skin at the time of surgery, patient allergy to the suture or the molecules produced as the suture dissolves, and the length of time required for a given suture to be absorbed.   Your surgeon has carefully chosen the suture he or she uses based on their personal experience. No surgeon wants to see his patient go through any unnecessary drama. and the fact that a patient spits dissolvable suture in no way means the surgeon did anything wrong. It is a situation that will eventually get better.

It is common to spit dissolvable sutures after a breast lift.  On occasion they can be red and even form a small Whitehead before spitting.However if you are having significant tenderness and redness you should see your plastic surgeon for assistance at removal.  It is unlikely that all of the sutures will spit as usually it is only the ones closest to the skin.