Yes, there is a difference between "my friend" and "a friend."
My Friend: When you refer to someone as "my friend," you are using a possessive pronoun ("my") to indicate that the person you are talking about is someone you personally know and have a specific relationship with. It suggests a level of personal connection and familiarity. In this case, the person is someone you consider to be your friend, and you likely have a history of shared experiences and mutual trust.
A Friend: On the other hand, when you refer to someone as "a friend," you are using the indefinite article "a" to indicate that the person you are talking about is a friend in a general or non-specific sense. It implies that the person is a member of a broader category of friends but may not necessarily be someone you have a close or personal relationship with. In this case, you are not specifying a particular individual, but rather referring to the idea of friendship in a general way.
To illustrate the difference:
If you say, "My friend John invited me to his party," you are talking about a specific person named John who you have a personal connection with.
If you say, "I made a new friend at the event," you are referring to a person you recently met and developed a friendship with, but you are not giving any specific details about who that person is.
In summary, "my friend" indicates a specific and personal relationship, while "a friend" refers to the concept of friendship in a more general or non-specific manner.