I have lymph node enlargement.....I am 25 years old male. I am having it since a week. I consulted a doctor but he said its just am enlargement....?

Depends. If you have an isolated finding of a lymph node without any other symptoms such as weight loss, fevers, night sweats, it may be a benign phenomenon. If it persists beyond a few weeks or enlarges, more tests may need to be done to make sure it is not a more serious problem.