Is it usual that an internist wants an echo test before changing my b/p medication. An EKG was already performed.

He said that after the ECHO he'll see how aggressive he has to be with the medication. Is this true?

The test will reveal any enlargement or other damage to the heart. If there is any,
then you bp target should be lower than the usual 140/90.

As pal says,
it's important to find out whether the heart is enlarged or any of the heart walls thickened from pumping for a long time against high pressure.
Consider it a routine part of good care; they used to just use a chest x-ray which usually just showed dootle!