If I had a nickel for every time I heard a story about someone who had been told by a doctor, there was nothing wrong with them that they could find and "it must all be in your head," I would be a rich woman! Unfortunately, when a doctor is stumped, sometimes they will use this as the final answer, instead of continuing the investigation process, as they should. Studies reveal that sadly, this scenario occurs often with male doctors and women patients. I am not trying to make any general statements here and imply that male doctors all dismiss women patients. I am relaying the statistics as they are, which demonstrate that male doctors will tend to lean more toward assuming a woman is exaggerating a symptom or condition, if they cannot find anything on a first round of testing and examination.
This circumstance DOES also occur with female phsyicians, as well and with male patients. At the end of the day, the point here is, "if", you feel there is definitely something physically wrong with you and you are quickly dismissed by your current doctor, and told they find nothing wrong with you, don't let it stop there.
You know your body. You know if what you are experiencing is not normal. Listen to your instinct! That is why we have one! Ask your doctor for a referral to a specialist. If you don't need a referral, go get a SECOND or THIRD opinion on your own. Do some research. Continue until you are satisified with an answer. Even if it means making an appointment with a counselor or psychologist to see if what you are experiencing may be a mental issue causing physical symptoms.
Don't just LISTEN to ONE person's opinion - there is nothing wrong with you - it's all in your head! So many of THOSE people then wind up in my office and explain how after months, or even years, of being told they were fine, they ultimately are diagnosed with a terminal cancer or life threatening disease that could have, and should have, been treated earlier.
While these scenarios may keep me busy at my job, I would rather have you listen to your instinct and do the right thing for yourself. Continue until you get someone to listen and give you the right answer and treatment. Ask for help of other physicians you see regularly. Find a patient advocate to speak to. Ask family and friends for assistance, but don't sit by and feel sick, or in pain, until you know why.
Stand up for yourself and what you believe in. Never let anyone in the medical profession intimidate you so much that you don't ask for help when it's necessary.