Thanks for contacting HCM for your health query.
Irregularity in your periods seems to be related to your obesity. This obesity may be the cause or reason of a condition called as
Polycystic Ovarian Syndrome (PCOS). In this condition the eggs in the ovaries get matured but they cannot be released. There is
hormonal imbalance in this condition which leads to irregular menses. The other features of this condition are obesity and hair on the unwanted parts of the body like face, abdomen and sometimes chest. The fine hair on the legs become more course. So please check for these features also.
The lump in your vagina is likely to be
fibroid which also can cause irregular and
heavy periods. Usually they are associated with pain in abdomen. This is usually a firm lump. Since you mention it to be hard, it is more likely to be fibroid.
The other theoretical possibility of the lump could be that either your uterus or
rectum or
urinary bladder might have descended in the vagina. But that should not cause the menstrual problems that you are describing.
However it is better to get examined by a
ObGyn physician to confirm the diagnosis of the lump.
Though your menstrual problems can be managed by hormonal medicines, I would advice you to get the diagnosis of the lump first. If it turns out to be a fibroid or any other growth coming from the cervix; i.e. mouth of the uterus, then that calls for the surgical intervention which will take care of the menstrual problem also.
Lastly, let me appeal you, when you post such problems, please mention your age and the number of children you have.