Hi, I had gone through your question and understand your concerns.
Swelling in the womb causes are many.
May be you are anxious to conceive.
If some thing is there it should be visible in
ultrasound .Any swelling in the abdomen should be palpable and changes its size with position of the body according to the cause of swelling.
You did not mentioned any other complaint like nausea ,
vomiting,
irregular periods,
constipation.
According to the symptoms diagnosis can be elicited.
When you felt something with your hand check whether it is increase in size with cough,in a condition named
HERNIA there is a swelling in the abdominal layers, which changes its size .
Consult a surgeon get a bedside clinical examination.
Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions.