I seen a lot of people have this particular question and the question that I have for them is what isn't free will?
On the religious side you've got the people who are saying God knows everything so he already knows what you're going to do. On the science side you've got all humans are just chemicals in a hot dog casing.
My opinion is, either which way you look at it you are free to choose what you want to do.
Just because somebody can make you question the freedom of your choices does not mean that your choices are not born of free will.
Here's my take, and you can do with it as you will.
We don't have free will, how could we? We are, as you said, chemicals in a hot dog casing. When I see something I want to eat, it's because chemicals tell me I'm hungry and it will provide sustenance. When I do something that I enjoy, and want to pursue, my brain is receiving chemicals that it enjoys, and tells me to continue doing actions that produce said chemicals. I can choose to do these things or not, but my choice in and of itself is determined by... more chemicals.
But why does it matter, if those chemicals also tell "me" that "me" is the one in charge?
It's like the cave/ shadow metaphor (that I will poorly paraphrase and misuse); hold a chair in front of a candle, show me the shadow, call it a "table" for my entire life, and the first time I see a chair I will say, "so this is what a table looks like!" It doesn't matter that it's actually a chair, just like it doesn't matter if I actually am making my choices. My reality (and your reality) is what I perceive and accept, and nothing more. Logically, I understand that when presented the choice between A and B, my body and the chemicals composing it are the ones "making" the decision, and I'm just acting it out. I get that. But if someone says, "do you want really want to watch The Lord of the Rings again?" I already know that the world has changed, because I feel it in the water, feel it in the earth, and smell it in the air.
I mean, if you were mindless and hungry you would eat the first food that came your way.
But you are not mindless and so you choose whether to eat a sandwich or a burger or a pizza and what kind of sandwich or burger or pizza it is.
You can choose to abstain from eating to lose weight or for religious purposes.
There is a part of you that has choice and control.
And even if that is a bioelectric chemical process, it's not always in charge, there is no one standing piece of you that is always entirely completely in control.
But there is always an observer. A sense of self.
And depending on the chemicals in your brain that observer will make different choices either positively or negatively for you as an entity.
You can look at it and say it is just chemical reactions but who is to say that Free Will is not a chemical reaction?
What if there are literal chemicals in your brain that can undergo their chemical processes in different ways based on the choices you make?
There's this nice dialog that's written by logician and taoist Raymund Smullyan that is about a man asking god to abscond him off free will. I will not spoil the plot but it has some great turns and offers insights on the absurdities and (im) possibilities of the desire not to have free will (and of talking to god).
It's a long read, mind you but it may give you more insight on what you want to know about.