ribs aching, breathless

I have been getting aching in my rib cage for almost a year now

I have been to the hospital with this about 6 months ago, and they did ecg, bloods etc and kept me overnight to do the same tests the next day. They told me all was ok and that its probably muscular

I have had lots of other heart tests too around 3-4 years ago

I have also visited my doctor with it twice, and they didn’t seem concerned. Last time I went they sent me for a chest x-ray but it came back clear

I seem to get it at night a lot in bed. When I lie down my nose seems to get blocked and my ribs ache. Last night had it was aching quite a lot and when I got up. It seems to have eased a little now, around 3 hours after getting up

I do feel breathless sometimes, but as I have a lot of symptom anxiety I am wondering if its just my mind making things worse

I do try and get some exercise, 40 mins brisk walks, some cycling etc, and so far the symptoms haven’t got worse when exercising

Any ideas whats going on?