Can someone give me any idea?

I am 22 years old in December ill be 23. As far back as I can remember I have always had knee pain I remember having knee pain when I was 6 or 7 years old..

Right now both of my knee caps are stinging and burning so bad that ill probably have to take some ibuprofen so I can sleep tonight.

I have been to many doctors throughout my life and they all have said it was just growing pains and they will eventually stop, but as of now they are not stopping. When I do activities they will hurt and ache..

When I sleep my Fiance can tell that I'm in pain because I will cry and groan when I'm sleeping he massages my knees a lot..

During my periods my knees hurts 10 times worse. Its actually worse than having period cramps. I'm 22 years old and I don't think this is Growing pains. I have even been to Hospital but didn't get any answers. Does anyone else hurt like this or have any ideas?