First off let me give you the definitions of subjective and objective data.
Objective data is information that you can perceive using your owns senses. Things that you can see, hear, smell, feel, sometimes taste, and sometimes measure objective data.
Subjective data is information supplied to you by the patient. They are things that you cannot yourself perceive with your senses of sight, sound, smell, or touch. For example, pain........ a patient tells you they have a pain in their leg. That is subjective data. It is based on the patient's statement for example........you cannot see, hear, smell, or feel the patient's pain. However, you can see a grimace on the face of someone in pain. tTe grimace on their face would be an objective observation.
The easiest way for me to remember is
Subjective= pt stated (symptoms)
Objective=Observed (by yourself, labs, during assessment,etc)