Child having chest pain on running, tiredness on climbing steps, is always warm. Is this normal?

My child has strong muscles and loves free play, but naps have lingered to age 7 1/2 and she has sought/needed several hours of downtime each day in the past 2-3 years. When younger, she never stopped. It just feels different. Then last year, she said her chest hurts when running around in gym or on the playground, and today she brought it up again (thought that was in the past). Also today, for the first time, she said that stair climbing makes her very tired. She has a lot of natural athletic talent but isn t getting into sports as much as kids with LSD talent, saying she d get too tired. And she s always hot or warm , she rarely needs a jacket until it s freezing outside and touching the back of her neck proves she s a little microwave. Do we need a cardiologist or second pediatric opinion, or is this all normal? Thanks.