Butt and Back pain

Hi my name is Mike I will try my best to keep this short
I use to be a fat unhealthy guy but one day I decided to change all that.
I started to get back into shape. My back and butt pain is not caused by working out, it just happened. I worked at a office job for a long time so I quit then I decided to work at a more physical job, nothing crazy just something that involves foot work and a lot of repetitive movements.
After awhile my back was getting stiff and painful so I quit and decided to go to univ. My girlfriend said go get a deep tissue massage. So I did!
I said my upper back and lower lumbar was sore and stiff and I'm getting warm sensations on my left outer leg by my shin when I sit. So the guy did his thing and I felt good after but I still have pain in my back, but my left butt cheek HURT a lot! I couldn't sleep, sit, crouch, NOTHING! but a few weeks passed and the pain in my butt slowly went away but I still have pain in my left butt cheek..the warm feeling sensation frequency of occurrence was cut in half.
Now my butt doesn't hurt 24/7, only when I sit at certain angles like on my couch, It doesn't hurt when I sit at the office chair nor when I jog or ride a bike. Only when I sit on my couch? should I just buy a new couch? LOL but I do notice I get a dull achy pain when I sit on the toilet. When I do sit on the couch I stand up the the butt pain is gone or when I lay opposite of the involved but cheek.
My doctor said I might have Bursitis or muscle strain in the butt or even Tendinitis he said take some NSAID and you will be fine...I have a weird look on my face when he said that.
Lastly my back, my back is stiff on the left middle side when I arch my back and when I bend over my legs are straight and I take both my hands and touch my Right foot the left side of my lower back stings..sharp pain.
it only hurts when I do that. The pain started when I sitting and I leaned forward to grab the T.v remote and BAM! I will stop now but just to let you people know I am now a semi-fat guy that is healthy just with some odd aches and pains. So if you can help in any way please post a reply I will be looking forward on seeing if anyone can properly determine what I do have I just one a clear answer not a "I think it's this..or this..but take these it will help the pain" I don't want to mask the pain I want a cure!

thx from the no so fat guy anymore Mike.

no help? no advice? ok let me put it simple, when I stand and arch my back the middle of my left back aches but when i bend forward it doesn't ache
and my lower left lumbar hurts only when I twist and bend down to the right so what does this mean? spinal joint problems? muscle strain/sparin?
my doctor took an x-ray and he says he doesn't see anything and he said my pain will go away in 2 weeks it's been 1 month so any takers?

hello Mike，i'm a student, just finish my 1st semester~~
Let us just wait and see whether others physiotherapist give any advise or not.
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