Is a Firm mattress right for me?

Hi, I previously had the artisan mattress, initially I had the medium, but felt it was too soft for me, I then changed it to a firm one within the 60 day guarantee, but still didn’t really get on with it, I would wake up stiff each morning.I changed last year to a Simba mattress and instantly felt more comfortable, however, 9 months later and I have started developing pins and needles in my arms and legs, and think it maybe mattress related.I have a history of neck problems, which results in these type of symptoms. I’m a side/front sleeper, I’m 6 foot 2 and weigh just under 14 stone.I’ve noticed that you now do a medium/firm tension, which may be a good compromise for me.Any thoughts will be appreciated.ThanksMark