Welcome to NeuroTalk:

Do you mind telling me how old you are?

A tendon strain can happen, and not manifest for a while.
I fell on my left knee years ago...but a month later the
ligaments on my adductor muscle flared up. They were strained
and I continued to work and stand.

Did they tell you to ice the area? That will calm down nerves that may be pinched with inflammation.

Pain in the hip may refer to this location as well. If icing 2 or 3 times a day and some anti-inflammatories do not work, then
you'll have to have further examination.
possiblities include:
1) Hip joint (have you taken steroids lately?--this can cause necrosis of the hip joint)

2) strain of the ligaments holding the hip, or the adductor muscle that goes from the groin connecting to the pelvis, to the inner knee

3) Some inflammation or hernia in the lower pelvis. In females this can include the ovary.

Many strains heal up ...but they are not fast in this regard.
I had to go to physical therapy for ultrasound and Ifc treatments for mine.