Human Right To Die?

We all know about the right to life, it is the most fundamental of rights, the most basic and the most universal. We all live therefore we have a right to continue living. Right? Well it's actually a lot more complicated than that!For example, do serial killers deserve to live? Do political dictators? When does life start? Does a foetus have the right to life? Does every egg and every sperm? Do people in the Armed Forces relinquish their right to life if killed in the call of duty? Can people kill in self defence? and is there such a thing as the Right to Die?
The Right to Die is not mentioned or even touched upon in the Universal Declaration of Human Rights (UDHR), there is basically no rule about it. "Article 3: Everyone has the right to life, liberty and security of person." So what happens if you are terminally ill, you are of stable mind and you are ready to end your life? If we each have a right to live then shouldn't we also be able to take it into our own hands when we decide to die? Since 1961, British law no longer prosecutes those who attempt suicide, so if a terminally ill person is able to take their own life by themselves they are not breaking the law. However, if someone is unable to take their own life, if they are physically unable to take their own lives, then they are deemed to suffer. The injustice of this is clear when put  in black and white like this, if you cannot take your own life you must suffer and die painfully and in an  undignified manner. Does the UDHR not say under Article 5: "No one shall be subjected to torture or to cruel, inhuman or degrading treatment or punishment"?