Your weak quadriceps muscle is feeling overworked and overused. The weakness is due to poor sitting and when this muscle is exposed to activities that the muscle feels stressful (repetitive sit to stand, stairs, exercises, kneeling) it gets irritable and give pain. MRI will only tell you the structure of the muscle but you have to analyse the function.

Hello !! If u have consistent pain since 4 months you should get it diagnosed and investigations will help in that process !! Get it checked physically or consult online . MRI is the ultimate option but is it necessary to get MRI is the question which will get clearer by examination. Just to rule out spine problems do u have back pain associated?

Most likely quadriceps tendinitis due to over use , need to give it some rest , followed by quadriceps conditioning programme .