I have been playing guitar for 7 years and have been attempting to write songs for about 5 years. I have an obsession with catchy melodies that stick in your head for days. The issue is, ive never wrote one. Im pretty good with lyrics but not melodies. Ive tried humming and mumbling over the music. Ive tried messing around with scales but nothing seems to work. Any advice? Any specific techniques you use? I know this is for sharing and critiquing but I'm really at a loss. Thanks in advance.
So, how are you at writing chords? If I have a chord progression that I like, and I write lyrics to go over it, and I sing the lyrics over the chords a few times, the words seem to naturally / effortlessly land on note within the key of my song. I may even start out just speaking the lyrics over the chords, and I gradually find myself making subconscious choices on adjusting the pitch, and after a few times through, I'm singing the lyrics. I do not even know what the notes are, but I hold up a tuner by my mouth and sing into it and figure out what "melodic line" I've come up with.

If I'm looking at lyrics with no chord progression for guidance, I'm lost trying to come up with a melody. So I always start with the chord progression. But that's just me.

There's other "rules" you can find, like generally moving stepwise with lyrics, and each time you jump more than a step, reverse direction and move stepwise back towards where you came from (e.g., A - B - C - D - G - F - E - A - B - A - B - A - E - D - C - C ).

Lately, I've been using a new approach to the melody, which is recording my chord progression and then just jamming over it, often using the above "rule" and often using chord tones, but sometimes not, and recording it. After a few times through, I find melodic lines that I really like with the chord progression, and then I imagine lyrics that could be sung to that melody, and use that to start the lyric-writing process. It's mostly because I hate writing lyrics, so I put it off as long as possible.
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What i do is 1. keep it simple
2.Get a chorus going,refer no.1
3 don`t be afraid of repeating lines that really work.
4. break all the rules,do your own thing.
5. a song is what you make it,if it`s only 1 minute so be it.
5. Don`t over think what you doing.
6. Enjoy!
Let me know if this helps?
here's a random bit of advice that might be helpful-

basically any melody you make is going to function based on your chord progression (and vice-versa). if you play a given set of notes over different chords, those set notes will still sound differently against each chord. this sounds incredibly obvious but is useful when you are actively listening for it.
Another approach is to compose a rhythm first, then add the notes to form the melody. Try thinking of the rhythm then clapping a pattern or writing it in notation (not on stave but on blank sheet). You might alter the rhythm as the melody comes together.