Depending on who/how the install was done, assuming the pipe is perforated, maybe someone forgot to 'wrap' it and the gravel (if any) in Filter Fabric or Landscape Fabric. Perf pipe has 'ridges' in it and it's EASY for 'stuff' to start building up and end up clogging.
If there isn't a clean-out along the way, you could dig it up, in sections, and put one in. Make sure the clean-out 'points' down stream. You want it to 'push' stuff OUT the line; not up the line, if you know what I mean.
My best to ya and hope this helps.
Jay J -Moderator
PS: As far as Roto Rooter doing the job, you'll have to ask them ...