58C would have me worried, for sure. If it hovers at that during idle, it might run close to the upper recommended thermal limit at full load. However, intels stock heatsink and fan should run the cpu at safe temperatures at minimum noise level. While it might be uncomfortable to experienced DIY computer enthusiasts, it should not be dangerous.
If possible check the temperatuer in your case. If the ambient temperature in the case are ~40C, then 58C is not that high. It is pretty hard to make a CPU run at the ambiend case temperature (and impossible to get it to run lower than that on air).
A rule of thumb is that a CPU should not go more than 10-20 degrees hotter than the temperature in the case. If you have a high end video card in there, it also contributes to heat, something that is worth considering. If you are worried, and have an ambient case temperature about 10-15 degrees lower than the CPU temp. Try to optimize the airflow through the case. It might be a good idea to try to see if a dedicated fan pointing towards the CPU decrease the CPU temperature, if so you have get a better airflow to utilize the airflow better.
Also, dont forget to take into account the ambient room temperature. As this is the basic temperature anything in your computer will begin to work at. But I guess I am writing a lot of things that are unecessary on this forum, rife with enthusiasts...