腰痛と肩こり！

I had a backache 2 weeks ago.
It was very painful, however it has gotten better.
I often get backache or neckache because my posture is bad.
My shoulders are always tense.
I do stretches/stretching exercises every night before I go to bed. (your sentance was perfectly acceptable, it just sounds more natural this way)

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Your English is going well, good job! :)

腰痛と肩こり！

I had a backache 2 weeks ago. It was a bad pain, but I have gotten well. I often have backache or neck ache because my posture is bad. My shoulders are tense all times.
I do stretching exercises before sleeping, every night.

Hello Tomomi, 

Many people these days have problems because of bad posture but they often don't realise it. It is good to do exercises, I did yoga when I had problems and found it helped a lot.

Just a couple of mistakes, well done.

Bob