In reply to Ava Adore:
I have heard the term "runners knee" applied to every knee pain there is from what you have said to illio-tibial band problems and even torn ligaments. So in that way it is non-descriptive.
For what it's worth, I had a knee injury mis-diagnosed as patello femoral syndrome by a GP and I was told to rest and take anti-inflammataries. I can't tell you how long to recover because that wasn't the problem.
If you genuinely can't afford even one session with a physio or sports therapist (£25-£40) at all, get a GP referal (may be 12 weeks to wait) and in the meantime describe your symptoms fully on here and you might get a friendly (qualified) person who will give you some pointers!
I went to the GP with ankle trouble and had it seen by a consultant, sent for an MRI and back to the consultant within 3 weeks so it's always worth trying the NHS route. Conversely I've had 6 weeks to wait to even make a physio appointment before.