Have i found a lost tampon or my cervix?

That's a strange: question, as a tampon would have a string attached and can be removed while obviously your cervix cannot. see doctor or OBGyn if you are still not sure

Removable?: Really, nobody can answer that question for you unless they are with you. If you can remove it, then it is not your cervix. A tampon can't really get lost - there is a finite amount of space in the vagina; however, if you are concerned that there is a foreign body/tampon "lost" you should see your GYN for a speculum exam immediately to reduce risk of infection.