Elliptic curve cryptography usually implies Elliptic Curve Diffie-Hellman (and/or digital signatures).
Diffie-Hellman is a key agreement algorithm, rather than a public-key encryption algorithm. You can not use it to "directly" encrypt your message.
Diffie-Hellman allows two parties to arrive at a mutual shared secret. Once you have a shared secret, encryption is (relatively) easy: Derive an encryption key for a symmetric (authenticated) cipher using the shared secret, and then use that key for encryption.
Using public-key cryptography to share a secret, then using that for symmetric cryptography is frequently referred to as "hybrid encryption".
You could cobble together an RSA-like construction using elliptic curves. But there is no advantage to doing so.
Indeed, in many if not most situations, you don't really want "public-key encryption".
Even if you have public-key encryption (meaning you can a priori select a message rather than generating a shared secret), it's usually a better idea to use it to encapsulate a key and use that for symmetric encryption than it is to use the public-key encryption algorithm to send your message.