It's been 3 and a half months after acl surgery and swelling comes back!?

Ok, so i tore my acl and lateral meniscus. Had surgery. It has felt fine the whole 3 months and 2 weeks so far. My physical therapist massaged it tuesday. That night it started popping when i would fully straighten it and bend it to about 90 degrees. Then wednesday it started to hurt when i bent it. And it was still popping. Now today, thursday, its still popping when i straighten fully and bend to about 90 degrees. And also it wasn't swollen at all. It had all went away. And now it's swelled right back up. The ACL graft still feels tight. Anyone know the problem?