Hi
Thank you for your query
You should visit a surgeon soon. Most likely it won't be anything serious but a certain things like
fracture of the ribs or/and
coccyx (tailbone) may require X rays and medical care. It is important to rule out anything serious. Till that time apply some ice packs on the chest and the tail bone area. Try to sit on a soft pillow every time rather than a hard surface. Since you also feel constipated a visit to the surgeon is worthwhile
Hope that helps
God bless you