Hi There, So I Have Had Lower Back Ache For

hi there,
so i have had lower back ache for the past month now and has been getting worse.
It's on my lower left side of the spine. I can feel what's like bubbles if i press gently.
I think it's a little swollen but it seems to be a soft swelling.
I am 26, I dance and keep fit but I have never experienced this before.
Sometimes i say a loud 'ouch' out as it is really painful with a movement and it's not like me at all.
please can you give me an idea as to what it could be?
I have made an appointment with the doctors, but it's a couple of weeks away.
I have looked online and as you may know, It's hard to get an idea of what symptoms are.