Just a thought, but have you had your Vit D , B12 checked?
I am sorry to hear about your pain. At your age I would be inclined to think that this may be a muscle, ligament or tendon issue. However it is also possible that it is spine related.
The hip contains the largest bursae in the body. A condition called Trochanteric Bursitis which simply means bursitis of the bursae of the hip can be very painful and cause the symptoms you describe. I have had it several time and an injection of a steroid into my hip always clears it up. The pain travels into my knee and down the front and sides of my thigh. Please don't think that I am saying that is what you have as I am far from an expert. It's just a possibility to consider.
The quadriceps muscles are the muscles on the front of the thigh. They consist of the Vastus lateralis, Vastus medialis, Vastus intermedius and the Rectus femoris. A strain, sprain or inflammation of any of those muscles can also cause your symptoms, including pain that radiates into your hip. The pain can vary in intensity depending on the type and/or amount of injury or inflammation. We can injury our muscles and supporting structures without even being aware of the fact.
Your pain does not sound like sciatica, a term used to describe sciatic nerve pain a symptom not a condition. More often that pain results from a back injury as the nerve is compressed or irritated.
It would imagine that it is possible that your back injury can be causing referred pain to your hip that travels down the front of your thigh and into your knee. It's much less common than referred pain down the back of your leg.
I suggest that you consult with an ortho specialist or your PCP. Chiropractors are good at adjustments but usually not as good at diagnosing these issues. Please see your physician.
Last but not least are you receiving good pain management? It is an important part of the healing process.
I hope that you will let us know how you are doing. I will look forward to your updates with interest. Be assertive and find solutions and a diagnosis to your pain. Please keep in touch. Best of luck to you.