Good afternoon,

I am new to the site so please bare with me

I am worrying myself silly at the moment and I'm hoping it's ok to post on here and ask for some advise as I haven't been diagnosed. 
I have missed 2 periods in a row now and am definitely not pregnant - I am sterilised and have still done 7 pregnancy tests - all negative. I also have pain, it started in the shoulder and has now moved to between my shoulder blades and my neck feels stiffer but doesn't hurt to move. I am not needing to urinate all the time but when I need to go, I need to go. 
It doesn't hurt to touch or prod my stomach or abdomen. I also, not all the time, have shooting dull pains down my thighs and my knee.  
My stomach is definitely larger however, I am not sure if I am just putting on weight?? I can't shake cancer out of my head.

I know these are not 'normal' symptoms but just wondering if anyone has had any of these?

Thank you in advance for any responses. 

Take care everyone.