A cold can NOT turn into pneumonia. 

The cold itself cannot turn into pneumonia. Each illness is a different virus and pneumonia can also develop due to a bacterial or fungal infection whereas a cold cannot. You may develop a cold after being exposed to the virus by ingesting infected droplets from an infected person's sneeze or cough or by handling a contaminated surface such as a door handle. An illness like pneumonia does not spread in the same manner.

However, pneumonia may develop following a common upper respiratory infection in those who are very young, elderly or have weakened immune systems. If you fit any of these descriptions, you may be at risk. However, if you are a person of general good health, you most likely will not develop a more serious illness following a bout with a cold.

The Common Cold vs. Pneumonia

When first beginning to feel the onset of a respiratory illness, you most likely will not be able to tell whether it's just a cold or something more serious like pneumonia. Many of the symptoms mimic each other such as fever, cough and chills. However, the common cold and its symptoms usually does not stick around for long and usually does not require anything more than over-the-counter medications, liquids and bedrest.

You're Still Sick After Two Weeks

If what you have been experiencing has not improved over an extended period of time of over-the-counter medications, bedrest and other common cold remedies, chances are that you never had a cold to begin with. As stated previously, the early stages of pneumonia can mimic the common cold and, without a visit to a doctor, it is unlikely that you will be able to diagnose yourself as having a cold, influenza, bronchitis or pneumonia.