Is this pain from physical therapy?

Check with the physical therapist and ask why the increase in pain. More than likely it is the anterior cruciate ligament that is causing this escalation of pain. The medial collateral ligament is going to be painful also but it is the ACL that will cause the most pain. If the explanation given by the therapist doesn't seem correct to you then call the orthopedist. Use ice on the knee for fifteen to twenty minutes per hour. Follow the directions given by the therapist and orthopedist. Any questions should be directed at the therapist first as they are seeing you more than the doctor. Again if you are not comfortable with the answers you are getting from them then by all means talk to the doctor.