Does just gaining weight cure the physical problems of an eating disorder?

I know that it won't cure the mental aspects but what about physical? I started out sick and had my gall bladder out in April of last year. I didn't wont to put back on weight so I started dieting and excersising. I am just now realizing that I took it to far. I was still eating so I didn't think I had a problem. I was not eating enough for my activity level though. I am eating a lot more and starting to gain weight. I previously had symptoms of always being cold, chest pains that woke me up at night, and I lost my period for 3 almost four months (quit taking BC pills, not pregnant, seeing an OBGYN already). My lowest weight was 101 at 5'3 and 1/2." I am up to 105 now and planning to go around 110 to 115. The only thing that really worries me is the chest pains (HEART??) and infertility issue. I seen a doctor about the chest pains in October and he said it was costochondritus. I am not sure if my period stopped because of low body weight or coming off the pills.