Instinctually, we all do sell, in our personal and professional lives. You sold your merits to win your partner, date, or spouse. You sold yourself to get a job.
All members of a technology startup are selling in a way, through hustle, and sheer will.
But sales is a science and an art, and people can be coached. Some are better than others, but at least you should understand the basics, the vocabulary, the process, and what can work.
Coders, in particular, have probably not held a position where they are paid a living wage to find and close deals - i.e., get a customer to pay you money. Coders may have participated in a deal, but it's dramatically different once you're in the game full-time.
This presentation, which I offer as a conference call or in person style, outlines what I learned, as a computer science major and 'coder' before getting into direct sales several years ago.
Even if you do not end up in a sales career, learning the language is helpful, and makes you credible with your management and sales colleagues.
The knowledge can even position you to 'fake it til you make it' and earn a seat at the table, if you choose to switch careers.
Good luck, and good selling.