Micro-Electro-Mechanical System (MEMS) is a wireless networking technique in which the background data is monitored and collected using wireless sensor networks. An additional requirement in this technique is to store the data for future retrieval and analysis purpose. This makes data storage become a more fascinating issue in wireless sensor networks. In data storage approach using storage node in the network is to choose suitable positions for storage a node becomes an essential problem. In this paper the above mentioned problem is addressed in wireless sensor network without any of the topology assumptions. Firstly, modeled the problem about data storage positions in theoretical manner and the non efficient heuristic algorithm called Particle Swarm Optimization is proposed to find the suitable positions for k storage nodes while the total energy cost of data transmission is minimized. The algorithm is implemented in a wireless sensor network simulator. The results of the experiments show the feasibility and efficiency of the proposed heuristic algorithm.