You're welcome to use whichever Lender you choose (from the Real Estate Broker's recommendations or your own), however... you should realize that making sure your Lender performs if your responsibility.
In other words, if your Lender does not show up on the day of closing with the money for whatever reason, you are still in default on the "Contract to Buy and Sell Real Estate" (not your Lender) and you are at risk of losing your Earnest Money (and specific performance in the unlikely event that box is checked on the "Contract to Buy and Sell Real Estate"). Another way of saying this is: your Lender is not a party to the "Contract to Buy and Sell Real Estate" and so they have no consequences in the "Contract to Buy and Sell Real Estate" if they don't perform.
So, consider "testing" a new Lender carefully.
Ask your Real Estate Broker for recommendations.
You may want to consider at least reading through the Mortgage Broker Interview Questions for some ideas of what you might want to ask:
Mark complete once you've talked to 3 Lenders of if you've already decided which Lender you plan to use.
You can ask your Real Estate Broker for recommendations.
Mark this task complete once you've decided on a Lender to use.
Some people will opt to get quotes from multiple lenders. If you're going to do this, compare everyone on the same day so the rate is the same.
Also, have the Lender you think is most likely to be the one you'll go with pull your credit and then tell the other Lenders you're comparing what your credit score is. If you decide to go with them, you'll let them pull your credit then.
If you need a recommendation for a Lender ask your Real Estate Broker.
Mark this task complete once you've applied for a loan and been approved with the Lender you plan to use.