Thanks for your question on Healthcare Magic.
I can understand your concern.
Possibility of musculoskeletal cause is more for your
chest tightness.
But better to rule out heart diseases first.
So get done ecg, 2d echo and
stress test (trade mill test).
If all these are normal then no need to worry for heart diseases.
Sometimes during sun bed activity, you might pull your muscles and which cause you chest tightness.
So better to sit with proper back and chest support.
Apply warm water pad on affected areas of chest.
Avoid stress and tension, if you have any.
Don't worry, you will be alright with all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.