Question
We live in ohio and the lawn in the back and sides of our home has some soft spots as we walk across the lawn and step on one of these soft spots it causes some concern is this a sign we should have investigated thanks the rest of the lawn is hard and firm

Answer
David:

There are several qualifiers on your lawn condition which may help to narrow the possibilities:

after rain, lawn wet?
dry for a long time?
are soft spots in lines?
how old lawn?
irrigation system in lawn?

The causes could be damp spots, moles, something rotting below the surface, or, hopefully not, a rock formation below the soil surface eroding, to mention a few.

I would dig into the lawn at those points to find what is causing the problem.  If wet spots, find the source(s) and note or repair.  If wood below surface, remove.  If moles, treat for grubs and hire a rat terrier.  Could be leaks in irrigation or water lines.

If the lawn is relatively new, different soils may produce this symptom.  Or there may be some biodegradable material below the soil surface rotting and causing a soft spot.

If in doubt, hire an old, experienced landscaper or ask your local ag extension agent.

Best wishes.