My betta has an odd lump on its chest

Question
Hi! I have a betta fish that I got about a 1 1/4 months. I
feed my betta regularly, and I change out its 5-gallon tank
water every two weeks, as recommended. However, something I
am doing must be wrong, because my fish has a lump on where
I'm guessing if it were a human, it would be her chest. My
betta is transparent, almost, and you can see her organs
pretty well through her scales. All I really see in the
enlarged area is what I am guessing are her lungs. I can
tell that this lump is not normal, and it is very swollen
looking. I have had many betta fish before, but none of
them have ever suffered this problem. The other bettas that
I have had were male, and this is my first female. I'm
wondering if her problem is gender related? This lump has
appeared and disappeared, leaving and coming back for about
a week at a time. Presently, the lump is as large as I have
ever seen it, which is what makes me seek help from someone
who knows what they're doing. I hope you can help me figure
out the problem! Thank you so much for taking your time.

Answer
Hello,
A lump on a fish is very hard to diagnose, almost impossible unless you see a vet.  Some lumps may be tumors.  They may, or may not be cancerous.  A Betta may live a long time with a tumor, it is a little like us.  It could also be a boil.  If this is the case, do not try to squeeze it, as this would cause her pain, and death.  It will come to a head on it's own.  There isn't much you can do for a lump except keep her in clean warm water.  She is a tropical fish, and needs 78-80 degree water.  If you must bring up the temperature, do this very very slowly.  One degree every two days.
Vary her diet, and feed her small amounts twice a day.  Example: 2 pellets for one meal.  She should also have one frozen cut pea with the outer layer removed once a week, and on the day you give her the pea, give her nothing else to eat.  This is to prevent Swim Bladder Disease.  Bettas are prone to constipation, and the pea cleans out their system.
You could try Betta fix, it is a natural medicine, and maybe it could help her.  
I'm sorry I cannot help you more, as she has nothing else I can go on.  If she is eating, this is a good sign.
I hope the lump goes away, if not, and she looks happy, then their is nothing more you can do, but treat her well, and keep her water very clean.  A 5 gallon tank should be changed every week.  Make sure she has no ammonia, no nitrites, and nitrates are safe in her water.
Lynda