It is probably not appropriate to ask your pastor to secure places for you to preach. It is best for you to prove your ministry in the local church and move through doors as Gods opens them. If your pastor offers to secure places for you to preach, that is good, but it is his call. However it is not the pastor’s responsibility to do so. Having said that, I am sure that your pastor will recognize the call of God on your life, and if you prove your ministry, he will direct you as to how to proceed in advancing your ministry.  I would communicate with the pastor and ask his advice on how I should get started and seek his council on how to get invitations to preach in other places. If you have the call, dedication, consecration and the ability to become active outside your local church, that will become obvious over time and doors will begin to open up for you . Even if the pastor thinks you’re capable and ready, does not mean that he can or should ask other pastors to let you preach.   Some times young men, in their zeal, feel they are ready to preach out before they actually are and that makes it hard for a pastor to tell them that they are not ready. I would submit myself to my pastor and trust him to guide you.   You should never be offended at your pastor for not getting you places to preach. He will have his own reasons that he may not convey to you.